Category Archives: History of Astronomy

They also serve…

In 1610, Galileo published his Sidereus Nuncius, the first publication to make known the new astronomical discoveries made with the recently invented telescope.

Source: Wikimedia Commons

Although, one should also emphasise that although Galileo was the first to publish, he was not the first to use the telescope as an astronomical instrument, and during that early phase of telescopic astronomy, roughly 1609-1613, several others independently made the same discoveries. There was, as to be expected, a lot of scepticism within the astronomical community concerning the claimed discoveries. The telescopes available at the time were generally of miserable quality and Galileo’s discoveries proved difficult to replicate. It was the Jesuit mathematicians and astronomers in the mathematics department at the Collegio Romano, who would, after initial difficulties, provide the scientific confirmation that Galileo desperately needed. The man, who led the endeavours to confirm or refute Galileo’s claims was the acting head of the mathematics faculty Christoph Grienberger (the professor, Christoph Clavius, was old and infirm). Grienberger is one of those historical figures, who fades into the background because they made no major discoveries or wrote no important books, but he deserves to be better known, and so this brief sketch of the man and his contributions.

As is all too oft the case with Jesuit scholars in the Early Modern Period, we know almost nothing about Grienberger before he joined the Jesuit Order. There are no know portraits of him. The problems start with his name variously given as Bamberga, Bamberger, Banbergiera, Gamberger, Ghambergier, Granberger, Panberger and a total of nineteen variations, history has settled on Grienberger. He was born 2 July 1561 in Hall a small town in the Tyrol in the west of Austria. That’s all we know till he entered the Jesuit Order in 1580. He studied rhetoric and philosophy in Prague from 1583 to 1584. From 1587 he was a mathematics teacher at the Jesuit university in Olmütz. He began his theology studies, standard for a Jesuit, in Vienna in 1589, also teaching mathematics. His earliest surviving letter to Christoph Clavius, who he had never met but who he describes as his teacher, he had studied the mathematical sciences using Clavius’ books, is dated from 1590. In 1591 he moved to the Collegio Romano, where he became Clavius’ deputy. 

In 1595, Clavius went to Naples, the purpose of his journey is not clear, but he was away from Rome for somewhat more than a year. During his absence Grienberger took over direction of the mathematics department at the Collegio Romana. From the correspondence between the two mathematicians, during this period, it becomes very obvious that Grienberger does not enjoy being in the limelight. He complains to Clavius about having to give a commencement speech and also about having to give private tuition to the sons of aristocrats. Upon Clavius’ return he fades once more into the background, only emerging again with the commotion caused by the publication of Galileo’s Sidereus Nuncius.

Rumours of Galileo’s discoveries were already making the rounds before publication and, in fact on the day the Sidereus Nuncius appeared, the wealthy German, Humanist Markus Welser (1558–1614) from Augsburg wrote to Clavius asking him his opinion on Galileo’s claims.

Markus Welser artist unknown Source: Wikimedia Commons

We know from letters that the Jesuit mathematicians in the Collegio Romano already had a simple telescope and were making astronomical observations before the publication of the Sidereus Nuncius. They immediately took up the challenge of confirming or refuting Galileo’s discoveries. However, their telescope was not powerful enough to detect the four newly discovered moons of Jupiter. Grienberger was away in Sicily attending to problems at the Jesuit college there, so it was left to Giovanni Paolo Lembo (c. 1570–1618) to try and construct a telescope good enough to complete the task. We know that Lembo was skilled in this direction because between 1615 and 1617 he taught lens grinding and telescope construction to the Jesuits being trained as missionaries to East Asia at the University of Coimbra. 

Lembo’s initial attempts to construct a suitable instrument failed and it was only after Grienberger returned from Sicily that the two of them were able to make progress. At this point Galileo was corresponding with Clavius and urging the Jesuit astronomer on provide the confirmation of his discoveries that he so desperately needed, the general scepsis was very high, but he was not prepared to divulge any details on how to construct good quality telescopes. Eventually, Grienberger and Lembo succeeded in constructing a telescope with which they could observe the moons of Jupiter but only under very good observational conditions. They first observed three of the moons on 14 November 1610 and all four on 16 November. 

Clavius wrote to the merchant and mathematician Antonio Santini (1577–1662) in Venice, who had been to first to confirm the existence of the Jupiter moons in 1610, with a telescope that he constructed himself, detailing observation from 22, 23, 26, and 27 November but stating that they were still not certain as to the nature of the moons. Santini relayed this information to Galileo. On 17 December, Clavius wrote to Galileo:

…and so we have seen [the Medici Stars] here in Rome many times. At the end of the letter I will put some observations, from which it follows very clearly that they are not fixed but wandering stars, because they change position with respect to each other and Jupiter.

Much of what we know about the efforts of the Jesuit astronomers under the leadership of Grienberger to build an adequate telescope to confirm Galileo’s discoveries come from a letter that Grienberger wrote to Galileo in February 1611. One interesting aspect of Grienberger’s letter is that the Jesuit astronomers had also been observing Venus and there is good evidence that they discovered the phases of Venus independently at least contemporaneously if not earlier than Galileo. This was proof that Venus, and by analogy probably also Mercury, orbit the Sun and not the Earth. This was the death nell for a pure Ptolemaic geocentric system and the acceptance at a minimum of a Capellan system where the two inner planets orbit the Sun, which orbits the Earth, if not a full blown Tychonic system or even a heliocentric one. This was in 1611 troubling for the conservative leadership of the Jesuit Order, but would eventually lead to them adopting a Tychonic system at the beginning of the 1620s. 

Clavius died 6 February 1612 and Grienberger became his official successor as the professor for mathematics at the Collegio Romano, a position he retained until 1633, when he was succeeded in turn by Athanasius Kircher (1602–1680). The was a series of Rules of Modesty in Ignatius of Loyola’s rules for the Jesuit Order and individual Jesuits were expected to self-abnegate. The most extreme aspect of this was that many scientific works were published anonymously as a product of the Order and not the individual. Different Jesuit scholars reacted differently to this principle. On the one hand, Christoph Scheiner (1573–1650), Galileo’s rival in the sunspot dispute and author of the Rosa Ursina sive Sol(1626–1630) presented himself as a great astronomer, which did not endear him to his fellow Jesuits.

Christoph Scheiner artist unknown Source: Wikimedia Commons

On the other hand, Grienberger put his name on almost none of his own work preferring it to remain anonymous. There is only a star catalogue and a set of trigonometrical tables that bear his name.

However, as head of the mathematics department at the Collegio Romano he was responsible for controlling and editing all of the publications in the mathematical disciplines that went out from the Jesuit Order and it is know that he made substantial improvements to the works that he edited both in the theoretical parts and in the design of instruments. A good example is the heliotropic telescope, which enables the observer to track the movement of the Sun whilst observing sunspots, illustrated in Scheiner’s Rosa Ursina.

Heliotropic telescope on the left. On the right Scheiner’s acknowledgement that Grienberger was the inventor

This instrument is known to have been designed and constructed by Grienberger, who, however, explicitly declined Scheiner’s offer to add a text under his own name describing its operation. Grienberger also devised a system of gearing theoretical capable of lifting the Earth

Reconstruction of Grienberger’S Earth lifting gearing

Grienberger, admired Galileo and took his side, if only in the background, in Galileo’s dispute with the Aristotelians over floating bodies. He was, however, disappointed by Galileo’s unprovoked and vicious attacks on the Jesuit astronomer Orazio Grassi on the nature of comets and explicitly said that it had cost Galileo the support of the Jesuits in his later troubles. He also clearly stated that if Galileo had been content to propose heliocentricity as a hypothesis, its actual scientific status at the time, he could have avoided his confrontation with the Church.

Élie Diodati (1576–1661) the Calvinist, Genevan lawyer and friend of Galileo, who played a central role in the publication of the Discorsi, quoted Grienberger in a letter to Galileo from 25 July 1634, as having said, “If Galileo had recognised the need to maintain the favour of the Fathers of this College, then he would live gloriously in the world, and none of his misfortune would have occurred, and he could have written about any subject, as he thought fit, I say even about the movement of the Earth…”

Several popular secondary sources claim the Grienberger supported the Copernican system. However, there is only hearsay evidence for this claim and not actual proof. He might have but we will never know. 

Grienberger made no major discoveries and propagated no influential new theories, which would launch him into the forefront of the big names, big events style of the history of science. However, he played a pivotal role in the very necessary confirmation of Galileo’s telescopic discoveries. He also successfully helmed the mathematical department of the Collegio Romano for twenty years, which produced many excellent mathematicians and astronomers, who in turn went out to all corners of the world to teach others their disciplines. By the time Athanasius Kircher inherited Grienberger’s post there was a world-wide network of Jesuit astronomers, communicating data on important celestial events. One such was Johann Adam Schall von Bell (1591–1666), who studied under Grienberger and went on to lead the Jesuit mission in China.

Johann Adam Schall von Bell Source: Wikimedia Commons

Science is a collective endeavour and figures such as Grienberger, who serve inconspicuously in the background are as important to the progress of that endeavour as the shrill public figures, such as Galileo, hogging the limelight in the foreground. 

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Filed under History of Astronomy, History of Mathematics, Renaissance Science

The deviser of the King’s horologes

There can’t be many Renaissance mathematici, whose existence was ennobled by a personal portrait by the master of the Renaissance portraits, Hans Holbein the younger. In fact, I only know of one, the German mathematicus, Nicolas Kratzer.

Nicolas Kratzer Portrait by Hans Holbein the younger

One might be excused for thinking that having received this singular honour that Kratzer had, in his lifetime, achieved something truly spectacular in the world of the Renaissance mathematical disciplines; however, almost the opposite is true. Kratzer appears to have produced nothing of any significance, was merely the designer and maker of sundials, and an elementary maths teacher, who was only portrayed by Holbein, because for a time they shared the same employers and were apparently mates. 

So, who was Kratzer and how did he and Holbein become mates? Here we find a common problem with minor scientific figures in the Renaissance, there are no biographies, no handy archives giving extensive details of his life. All we have are a few, often vague, sometimes contradictory, traces in the proverbial sands of time from which historians have attempted to reconstruct at least a bare outline of his existence. 

Kratzer was born in 1487 in Munich, the son of a saw-smith and it is probably that he learnt his metal working skills, as an instrument maker, from his father. He matriculated at the University of Köln 18 November 1506 and graduated BA 14 June 1509. He moved onto the University of Wittenberg, famous as the university of Martin Luther. However, this was before the Reformation and Wittenberg, a young university first founded in 1502, was then still Catholic. We now lose track of Kratzer, who is presumed to have then worked as an instrument maker. Sometime in the next years, probably in 1517, he copied some astronomical manuscripts at the Carthusian monastery of Maurbach, near Vienna. 

In January 1517, Pieter Gillis (1486–1533) wrote to his erstwhile teacher Erasmus (1466–1536) that the skilled mathematician Kratzer was on his way with astrolabes and spheres, and a Greek book.

HOLBEIN, Hans the Younger (b. 1497, Augsburg, d. 1543, London) Portrait of Erasmus of Rotterdam 1523 Wood, 76 x 51 cm National Gallery, London

This firmly places Kratzer in the circle of humanist scholars, most famously Erasmus and Thomas More (1478–1535) author of Utopia, who founded the English Renaissance on the court of Henry VIII (1491–1547). Holbein was also a member of this circle. Erasmus and Holbein had earlier both worked for the printer/publisher collective of Petri-Froben-Amerbach in Basel. Erasmus as a copyeditor and Holbein as an illustrator. Holbein produced the illustrations for Erasmus’ In Praise of Folly (written 1509, published by Froben 1511)

Holbein’s witty marginal drawing of Folly (1515), in the first edition, a copy owned by Erasmus himself

Kratzer entered England either at the end of 1517 or the beginning of 1518. His first identifiable employment was in the household of Thomas More as maths teacher for a tutorial group that included More’s children. It can be assumed that it was here that he got to know Holbein, who was also employed by More. 

Thomas More Portrait by Hans Holbein 1527

For his portraits, Holbein produced very accurate complete sketches on paper first, which he then transferred geometrically to his prepared wooden panels to paint them. Around 1527, Holbein painted a group portrait of the More family that is no longer extant, but the sketch is. The figures in the sketch are identified in writing and the handwriting has been identified as Kratzer’s. 

Like Holbein, Kratzer moved from More’s household to the court of Henry VIII, where he listed in the court accounts as the king’s astronomer with an income of £5 a quarter in 1529 and 1531. It is not very clear when he entered the King’s service but in 1520 Cuthbert Tunstall (1474–1559), later Prince-Bishop of Durham, wrote in a letter:

Met at Antwerp with [Nicolas Kratzer], an Almayn [German], devisor of the King’s horologes, who said the King had given him leave to be absent for a time.

Both Tunstall and Kratzer were probably in Antwerp for the coronation of Charles V (1500–1558) as King of Germany, which took place in Aachen. There are hints that Kratzer was there to negotiate with members of the German court on Henry’s behalf. Albrecht Dürer (1471–1528) was also in the Netherlands; he was hoping that Charles would continue the pension granted to him by Maximilian I, who had died in 1519. Dürer and Kratzer met in the house of Erasmus and Kratzer was present as Dürer sketched a portrait of Erasmus. He also drew a silver point portrait of Kratzer, which no longer exists. 

 

Dürer sketch of Erasmus 1520
Dürer engraved portrait of Erasmus based on 1520 sketch finished in 1526. Erasmus reportedly didn’t like the portrait

Back in England Kratzer spent some time lecturing on mathematical topics at Oxford University during the 1520s. Here once again the reports are confused and contradictory. Some sources say he was there at the behest of the King, others that he was there in the service of Cardinal Wolsey. There are later claims that Kratzer was appointed a fellow of Corpus Christi College, but the college records do not confirm this. However, it is from the Oxford records that we know of Kratzer’s studies in Köln and Wittenberg, as he was incepted in Oxford as BA and MA, on the strength of his qualifications from the German institutions, in the spring of 1523. 

During his time in Oxford, he is known to have erected two standing sundials in the college grounds, one of which bore an anti-Lutheran inscription.

Drawing of Kratzer’s sundial made for the garden of Corpus Christi College Oxford

Neither dial exists any longer and the only dial of his still there is a portable brass dial in the Oxford History of Science Museum, which is engraved with a cardinal’s hat on both side, which suggests it was made for Wolsey.

Kratzer polyhedral sundial presumably made for Cardinal Wolsey Museum for the History of Science Oxford

On 24 October 1524 Kratzer wrote the following to Dürer in Nürnberg

Dear Master Albert, I pray you to draw for me a model of the instrument that you saw at Herr Pirckheimer’s by which distances can be measured, and of which you spoke to me at Andarf [Antwerp], or that you will ask Herr Pirckheimer to send me a description of the said instrument… Also I desire to know what you ask for copies of all your prints, and if there is anything new at Nuremberg in my craft. I hear that our Hans, the astronomer, is dead. I wish you to write and tell me what he has left behind him, and about Stabius, what has become of his instruments and his blocks. Greet in my name Herr Pirckheimer. I hope shortly to make a map of England which is a great country, and was not known to Ptolemy; Herr Pirckheimer will be glad to see it. All who have written of it hitherto have only seen a small part of England, no more… I beg of you to send me the likeness of Stabius, fashioned to represent St. Kolman, and cut in wood…

Herr Pirckheimer is Willibald Pirckheimer (1470–1530), who was a lawyer, soldier, politician, and Renaissance humanist, who produced a new translation of Ptolemaeus’ Geographia from Greek into Latin.

Engraved portrait of Willibald Pirckheimer Dürer 1524

He was Dürer’s life-long friend, (they were born in the same house), patron and probably lover.  He was at the centre of the so-called Pirckheimer circle, a group of mostly mathematical humanists that included “Hans the astronomer, who was Johannes Werner (1468–1522), mathematician, astronomer, astrologer, geographer,

Johannes Werner artist unknown

and cartographer and Johannes “Stabius” (c.1468–1522) mathematician, astronomer, astrologer, and cartographer.

Johannes Stabius portrait by Dürer

Werner was almost certainly Dürer’s maths teacher and Stabius worked together with Dürer on various projects including his star maps. The two are perhaps best known for the Werner-Stabius heart shaped map projection. 

Dürer replied to Kratzer 5 December 1524 saying that Pirckheimer was having the required instrument made for Kratzer and that the papers and instruments of Werner and Stabius had been dispersed.

Here it should be noted that Dürer, in his maths bookUnderweysung der Messung mit dem Zirkel und Richtscheyt (Instruction in Measurement with Compass and Straightedge), published the first printed instructions in German on how to construct and orientate sundials. The drawing of one sundial in the book bears a very strong resemblance to the polyhedral sundial that Kratzer made for Cardinal Wolsey and presumably Kratzer was the original source of this illustration. 

Dürer drawing of a sundial

Kratzer is certainly the source of the mathematical instruments displayed on the top shelf of Holbein’s most famous painting the Ambassadors, as several of them are also to be seen in Holbein’s portrait of Kratzer.

in’s The AmbassadorsHolbe

Renaissance Mathematicus friend and guest blogger, Karl Galle, recently made me aware of a possible/probable indirect connection between Kratzer and Nicolas Copernicus (1473–1543). Georg Joachim Rheticus (1514–1574) relates that Copernicus’ best friend Tiedemann Giese (1480–1550) possessed his own astronomical instruments including a portable sundial sent to him from England. This was almost certainly sent to him by his brother Georg Giese (1497–1562) a prominent Hanseatic merchant trader, who lived in the Steelyard, the Hansa League depot in London, during the 1520s and 30s.

London’s Steelyard

He was one of a number of Hanseatic merchants, whose portraits were painted by Holbein, so it is more than likely that the sundial was one made by Kratzer. 

Georg Giese portrait by Hans Holbein 1532

Sometime after 1530, Kratzer fades into the background with only occasional references to his activities. After 1550, even these ceased, so it is assumed that he had died around this time. In the first half of the sixteenth century England lagged behind mainland Europe in the mathematical disciplines including instrument making, so it is a natural assumption that Kratzer with his continental knowledge was a welcome guest in the Renaissance humanist circles of the English court, as was his younger contemporary, the Flemish engraver and instrument maker, Thomas Gemini (1510–1562). Lacking homegrown skilled instrument makers, the English welcomed foreign talent and Kratzer was one who benefited from this. 

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Filed under History of Astronomy, History of Mathematics, History of science, History of Technology, Renaissance Science

An eighteenth-century cartographical community in Nürnberg

If you walk up Burgstraße in the city of Nürnberg in the direction of the castle, you will see in front of you the impressive Baroque Fembohaus, which from 1730 to 1852 was the seat of the cartographical publishing house Homännische Erben, that is “Homann’s Heirs” in English. But who was Homann and why was the business named after his heirs?

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Fembohaus Source: Wikimedia Commons

Johann Baptist Homann (1664–1724) was born in Öberkammlach in the south of Bavaria. He was initial educated at a Jesuit school and at some point, entered the Dominican Cloister in Würzburg, where he undertook, according to his own account, his “studia humaniora et philosophica.”

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Johann Baptists Homann (1664–1725) Portrait by Johann Wilhelm Windter (c. 1696– 1765) Source: Wikimedia Commons

In 1687 he left the cloister moved to Nürnberg and converted to Protestantism. Over the next ten years he vacillated between Catholicism and Protestantism, leaving Nürnberg during the Catholic phases, and returning during the Protestant phases. In 1691 in Nürnberg, he was registered for the first time as a notary public. Around the same time, he started his career as a map engraver. It is not known how or where he learnt this trade, although there are claims that he was entirely self-taught. A map of the district surrounding Nürnberg, produced in 1691/92, shows Homann already as a master in cartographic engraving. From 1693 to 1695 he was in Vienna, then he returned for a time to Nürnberg, leaving again for Erlangen in 1696. Around 1696 to 1697, he was engraving maps in Leipzig.

He appears to have final settled on life as a protestant and permanent residency in Nürnberg in 1698. In 1702 he established a dealership and publishing house for cartography in the city, producing and selling maps, globes, and atlases. His dealership also produced and sold scientific instruments. The field that Homann had chosen to enter was by the beginning of the eighteenth century well established and thriving, with a lot of very powerful competition, in particular from France and Holland. Homann entered the market from a mercantile standpoint rather than a scientific one. He set out to capture the market with high quality products sold more cheaply than the competition, marketing copies of maps rather than originals. In a relatively short time, he had established himself as the dominant cartographical publisher in Germany and also a European market leader.

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Planiglobii Terrestris Cum Utroq[ue] Hemisphærio Cælesti Generalis Exhibitio, Nürnberg 1707 Source: Wikimedia Commons

His dealership offered single sheet maps for sale, but he became the first German cartographer to sell atlases on a large scale and is considered the second most important German cartographer after Mercator. His first atlas with forty maps appeared in 1707. This was expanded to the Großen Atlas über die ganze Welt (The Big Atlas of the Entire World), with one hundred and twenty-six maps in 1716.

1716_Homann_Map_of_Burgundy,_France_-_Geographicus_-_Burgundiae-homan-1716-2

A fine example of Homann’s 1716 map of Burgundy, one of France’s most important wine regions. Extends to include Lake Geneva in the southwest, Lorraine in the north, Champaigne (Champagne) and Angers to the northwest and Bourgogne to the west. Depicts mountains, forests, castles, and fortifications and features an elaborate title cartouche decorated with cherub winemakers in the bottom right. A fine example of this rare map. Produced by J. H. Homann for inclusion in the Grosser Atlas published in Nuremberg, 1716. Source: Wikimedia Commons

By 1729 it had around one hundred and fifty maps. Johann Baptist’s success was richly acknowledged in his own lifetime. In 1715 he was appointed a member of the Preußischen Akademie der Wissenschaften (The Prussian Academy of Science) and in 1716 he was appointed Imperial Geographer by the Holy Roman Emperor, Karl VI.

1730_Homann_Map_of_Scandinavia,_Norway,_Sweden,_Denmark,_Finland_and_the_Baltics_-_Geographicus_-_Scandinavia-homann-1730

A detailed c. 1730 J. B. Homann map of Scandinavia. Depicts both Denmark, Norway, Sweden, Finland and the Baltic states of Livonia, Latvia and Curlandia. The map notes fortified cities, villages, roads, bridges, forests, castles and topography. The elaborate title cartouche in the upper left quadrant features angels supporting a title curtain and a medallion supporting an alternative title in French, Les Trois Covronnes du Nord . Printed in Nuremburg. This map must have been engraved before 1715 when Homann was appointed Geographer to the King. The map does not have the cum privilegio (with privilege; i.e. copyright authority given by the Emperor) as part of the title, however it was included in the c. 1750 Homann Heirs Maior Atlas Scholasticus ex Triginta Sex Generalibus et Specialibus…. as well as in Homann’s Grosser Atlas . Source: Wikimedia Commons

The publishing house continued to grow and prosper until Johann Baptist’s death in 1724, when it was inherited by his son Johann Christian Homann (1703–1730).

Johann Christian studied medicine and philosophy in Halle. He graduated doctor of medicine in 1725, following which he went on a study trip, first returning to Nürnberg in 1729. During his absence the publishing house was managed by Johann Georg Ebersberger (1695–1760) and later together with Johann Christian’s friend from university Johann Michael Franz (1700­–1761).

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Hand coloured copper engraving by J. Chr. Homann, showing noth west Africa with the Canary Islands and two large cityviews. Source: Wikimedia Commons

When Johann Christian died in 1730, he willed the business to Ebersberger and Franz, who would continue to run the business under the name Homännische Erben. The publishing house passed down through several generations until Georg Christoph Fembo (1781­–1848) bought both halves of the business in 1804 and 1813. Fembo’s son closed the business in 1852 and in 1876 the entire collection of books, maps, engravings, and drawing were auctioned off, thus destroying a valuable source for the history of German cartography.

Today there is a big market for fictional maps based on fantasy literature such as Lord of the Rings. This is nothing new and Early Modern fiction also featured such fictional maps, for example Thomas More’s Utopia (1516). One very popular medieval myth concerns the Land of Cockaigne, a fictional paradise of pleasure and plenty also known as The Land of Milk and Honey. The German version is Schlaraffenland (literally the Land of the Lazy Apes). The most well-known version of the myth in the seventeenth century was written by Johann Andreas Schneblins (d. 1702) and based on Schneblins’ account of his travels in the utopia of Schlaraffenland Homann produced a map his very popular Accurata Utopiae Tabula.

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“Accurata Utopiæ Tabula” (also named “Schlarraffenlandes”) designed by Johann Baptist Homann and printed in 1694 Source: Wikimedia Commons

From the very beginning one distinctive feature of the publishing house was Homann’s active cooperation with other scholars and craftsmen. From the beginning Johann Baptist worked closely with the engraver, art dealer, and publisher Christoph Weigel the Older (1665–1725).

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Christoph Weigel, engraved by Bernhard Vogel of a portrait by Johann Kupetzky Source:Wikimedia Commons

Weigel’s most significant publication was his Ständebuch (1698) (difficult to translate but Book of the Trades and Guilds).

Der Pulvermacher Kupferstich Regensburger Ständebuch 1698 Christoph Weigel der Ältere 1654 172

Gunpowder makers, engraving Regensburger Ständebuch, 1698, Christoph Weigel der Ältere (1654, 1725)

Weigel was very successful in his own right but he cooperated very closely with Homann on his map production.

Homann also cooperated closely with the scholar, author, schoolteacher, and textbook writer Johann Hübner (1668–1731).

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Johann Hübner, engraving by Johann Kenckel Source: Wikimedia Commons

Together the two men produced school atlases according to Hübner’s pedagogical principles. In 1710 the Kleiner Atlas scholasticus von 18 Charten (Small School Atlas with 18 Maps) was published.

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Kleiner Atlas scholasticus von 18 Charten

This was followed in 1719 by the Johann Baptist Homann / Johann Hübner: Atlas methodicus / explorandis juvenum profectibus in studio geographico ad methodum Hubnerianam accommodatus, a Johanne Baptista Homanno, Sacrae Caesareae Majestatis Geographo. Noribergae. Anno MDCCXIX. Methodischer Atlas / das ist, Art und Weise, wie die Jugend in Erlernung der Geographie füglich examiniret werden kann / nach Hübnerischer Lehr-Art eingerichtet von Johann Baptist Homann, Nürnberg, 1719. The title, given here in both Latin and German translates as Methodical Atlas in the manner in which the youth can be reasonably examined in the study of geography according to the pedagogic principles of Hübner, presented by Johann Baptist Homann.

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Charte von Europa. Charte von Asia. Charte von Africa. Charte von America. Johanne Baptista Homanno, Norimbergae, 1719 Atlas methodicus / explorandis juvenum profectibus in studio geographico ad methodum Hubnerianam accommodatus

Johann Gottfried Gregorii (1685–1770) was a central figure in the intellectual life of eighteenth-century Germany. A geographer, cartographer, historian, genealogist, and political journalist, he put out a vast number of publications, mostly under the pseudonym Melissantes.

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Johann Gottfried Gregorii Source: Wikimedia Commons

In his geographical, cartographical, and historical work he cooperated closely with both Johann Baptist Homann and Christoph Weigel.

 One of the Homann publishing house’s most important cooperation’s was with the Nürnberg astronomer Johann Gabriel Doppelmayr (1677–1750).

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Johann Gabriel Doppelmayr Source: Wikimedia Commons

Doppelmayr was professor for mathematics at the Aegidianum, Germany’s first modern high school, and is best known for two publication his Historische Nachricht Von den Nürnbergischen Mathematicis und Künstlern (1730), an invaluable source for historian of science and his celestial atlas, Atlas Novus Coelestis (1742). Doppelmayr had been supplying celestial charts for the Homann atlases but his Atlas Novus Coelestis, which was published by Homännische Erben, contained thirty spectacular colour plates and was a leading celestial atlas in the eighteenth century.

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PHÆNOMENA circa quantitatem dierum artificialium et solarium perpetuo mutabilem, ex Hypothesi copernicana deducta, cum aliis tam Veterum quam recentiorum Philosophorum, Systematibus mundi notabilioribus, exhibita – Engraved between 1735 and 1742.

Doppelmayr’s successor as professor of mathematics at the Aegidianum was Georg Moritz Lowitz (1722–1774), who went on to become professor for practical mathematics at the University of Göttingen.

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Georg Moriz Lowiz Source: Wikimedia Commons

He worked together with Johann Michael Franz and produced several astronomical publications for the Homännische Erben. Franz as well as being co-manager of the publishing house was also an active geographer, who became professor in Göttingen in 1755. He also published a series of his own books on geographical themes. He sold his share of the publishing house on his younger brother Jacob Heinrich Franz (1713–1769) in 1759.

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Johann Michael Franz: Belgium, Luxemburg; Johann Michael Franz – Circulus Burgundicus – 1758

Without any doubt Homann’s most important or significant employee, at least with hindsight, was the cartographer and astronomer Tobias Mayer (1723–1762), who is these days is best known for having calculated the Moon’s orbit accurately enough to make the lunar distance method of determining longitude viable. A self-taught mathematicus he had already published a town plan of Esslingen, two books on mathematics and one on fortifications, when he was appointed to the Homännische Erben in 1746.

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Tobias Mayer Source: Wikimedia Commons

It was during his time in Nürnberg that he did his work on lunar astronomy. Like Lowitz, and Franz, Mayer also became a professor in Göttingen, in his case for economics and mathematics.

The three Göttingen professors–Lowitz, Franz, and Mayer–whilst still working for Homann in Nürnberg founded the Cosmographische Gesellschaft (Cosmographical Society), with the aim of improving the standards of cartography and astronomy. Due to lack of funding they never really got their plans of their grounds. Their only products being some propaganda publications for the society written by Franz and one publication from Mayer on his lunar research.

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Each of the scholars, briefly sketched here was a leading figure in the intellectual landscape of eighteenth-century Germany and they were all to some extent rivals on the open knowledge market. However, they cooperated rather than competed with each other and in doing so increased the quality of their output.

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Renaissance Science – VIII

In the last two episodes we have looked at developments in printing and art that, as we will see later played an important role in the evolving Renaissance sciences. Today, we begin to look at another set of developments that were also important to various areas of the newly emerging practical sciences, those in mathematics. It is a standard cliché that mathematisation played a central roll in the scientific revolution but contrary to popular opinion the massive increase in the use of mathematics in the sciences didn’t begin in the seventeenth century and certainly not as the myth has it, with Galileo.

Medieval science was by no means completely devoid of mathematics despite the fact that it was predominantly Aristotelian, and Aristotle thought that mathematics was not scientia, that is, it did not deliver knowledge of the natural world. However, the mathematical sciences, most prominent astronomy and optics, had a fairly low status within medieval university culture.

One mathematical discipline that only really became re-established in Europe during the Renaissance was trigonometry. This might at first seem strange, as trigonometry had its birth in Greek spherical astronomy, a subject that was taught in the medieval university from the beginning as part of the quadrivium. However, the astronomy taught at the university was purely descriptive if not in fact even prescriptive. It consisted of very low-level descriptions of the geocentric cosmos based largely on John of Sacrobosco’s (c. 1195–c. 1256) Tractatus de Sphera (c. 1230). Sacrobosco taught at the university of Paris and also wrote a widely used Algorismus, De Arte Numerandi. Because Sacrobosco’s Sphera was very basic it was complimented with a Theorica planetarum, by an unknown medieval author, which dealt with elementary planetary theory and a basic introduction to the cosmos. Mathematical astronomy requiring trigonometry was not hardy taught and rarely practiced.

Both within and outside of the universities practical astronomy and astrology was largely conducted with the astrolabe, which is itself an analogue computing device and require no knowledge of trigonometry to operate.

Before we turn to the re-emergence of trigonometry in the medieval period and its re-establishment during the Renaissance, it pays to briefly retrace its path from its origins in ancient Greek astronomy to medieval Europe.

The earliest known use of trigonometry was in the astronomical work of Hipparchus, who reputedly had a table of chords in his astronomical work. This was spherical trigonometry, which uses the chords defining the arcs of circles to measure angles. Hipparchus’ work was lost and the earliest actual table of trigonometrical chords that we know of is in Ptolemaeus’ Mathēmatikē Syntaxis or Almagest, as it is usually called today.

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The chord of an angle subtends the arc of the angle. Source: Wikimedia Commons

When Greek astronomy was appropriated in India, the Indian astronomers replaced Ptolemaeus’ chords with half chords thus creating the trigonometrical ratios now known to us, as the sine and the cosine.

It should be noted that the tangent and cotangent were also known in various ancient cultures. Because they were most often associated with the shadow cast by a gnomon (an upright pole or post used to track the course of the sun) they were most often known as the shadow functions but were not considered part of trigonometry, an astronomical discipline. So-called shadow boxes consisting of the tangent and cotangent used for determine heights and depths are often found on the backs of astrolabes.

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Shadow box in the middle of a drawing of the reverse of Astrolabium Masha’Allah Public Library Bruges [nl] Ms. 522. Basically the tangent and cotangent functions when combined with the alidade

  Islamic astronomers inherited their astronomy from both ancient Greece and India and chose to use the Indian trigonometrical half chord ratios rather than the Ptolemaic full cords. Various mathematicians and astronomers made improvements in the discipline both in better ways of calculating trigonometrical tables and producing new trigonometrical theorems. An important development was the integration of the tangent, cotangent, secant and cosecant into a unified trigonometry. This was first achieved by al-Battãnī (c.858–929) in his Exhaustive Treatise on Shadows, which as its title implies was a book on gnonomics (sundials) and not astronomy. The first to do so for astronomy was Abū al-Wafā (940–998) in his Almagest.

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Image of Abū al-Wafā Source: Wikimedia Commons

It was this improved, advanced Arabic trigonometry that began to seep slowly into medieval Europe in the twelfth century during the translation movement, mostly through Spain. It’s reception in Europe was very slow.

The first medieval astronomers to seriously tackle trigonometry were the French Jewish astronomer, Levi ben Gershon (1288–1344), the English Abbot of St Albans, Richard of Wallingford (1292–1336) and the French monk, John of Murs (c. 1290–c. 1355) and a few others.

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Richard of Wallingford Source: Wikimedia Commons

However, although these works had some impact it was not particularly widespread or deep and it would have to wait for the Renaissance and the first Viennese School of mathematics, Johannes von Gmunden (c. 1380­–1442), Georg von Peuerbach (1423–1461) and, all of whom were Renaissance humanist scholars, for trigonometry to truly establish itself in medieval Europe and even then, with some delay.

Johannes von Gmunden was instrumental in establishing the study of mathematics and astronomy at the University of Vienna, including trigonometry. His work in trigonometry was not especially original but displayed a working knowledge of the work of Levi ben Gershon, Richard of Wallingford, John of Murs as well as John of Lignères (died c. 1350) and Campanus of Novara (c. 200–1296). His Tractatus de sinibus, chordis et arcubus is most important for its probable influence on his successor Georg von Peuerbach.

Peuerbach produced an abridgement of Gmunden’s Tractatus and he also calculated a new sine table. This was not yet comparable with the sine table produced by Ulugh Beg (1394–1449) in Samarkand around the same time but set new standards for Europe at the time. It was Peuerbach’s student Johannes Regiomontanus, who made the biggest breakthrough in trigonometry in Europe with his De triangulis omnimodis (On triangles of every kind) in 1464. However, both Peuerbach’s sine table and Regiomontanus’ De triangulis omnimodis would have to wait until the next century before they were published. Regiomontanus’ On triangles did not include tangents, but he rectified this omission in his Tabulae Directionum. This is a guide to calculating Directions, a form of astrological prediction, which he wrote at the request for his patron, Archbishop Vitéz. This still exist in many manuscript copies, indicating its popularity. It was published posthumously in 1490 by Erhard Ratdolt and went through numerous editions, the last of which appeared in the early seventeenth century.

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A 1584 edition of Regiomontanus’Tabulae Directionum Source

Peuerbach and Regiomontanus also produced their abridgement of Ptolemaeus’ Almagest, the Epitoma in Almagestum Ptolemae, published in 1496 in Venice by Johannes Hamman. This was an updated, modernised version of Ptolemaeus’ magnum opus and they also replaced his chord tables with modern sine tables. A typical Renaissance humanist project, initialled by Cardinal Basilios Bessarion (1403–1472), who was a major driving force in the Humanist Renaissance, who we will meet again later. The Epitoma became a standard astronomy textbook for the next century and was used extensively by Copernicus amongst others.

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Title page Epitoma in Almagestum Ptolemae Source: Wikimedia Commons

Regiomontanus’ De triangulis omnimodis was edited by Johannes Schöner and finally published in Nürnberg in 1533 by Johannes Petreius, together with Peuerbach’s sine table, becoming a standard reference work for much of the next century. This was the first work published, in the European context, that treated trigonometry as an independent mathematical discipline and not just an aide to astronomy.

Copernicus (1473–1543,) naturally included modern trigonometrical tables in his De revolutionibus. When Georg Joachim Rheticus (1514–1574) travelled to Frombork in 1539 to visit Copernicus, one of the books he took with him as a present for Copernicus was Petreius’ edition of De triangulis omnimodis. Together they used the Regiomontanus text to improve the tables in De revolutionibus. When Rheticus took Copernicus’ manuscript to Nürnberg to be published, he took the trigonometrical section to Wittenberg and published it separately as De lateribus et angulis triangulorum (On the Sides and Angles of Triangles) in 1542, a year before De revolutionibus was published.

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Rheticus’ action was the start of a career in trigonometry. Nine years later he published his Canon doctrinae triangvlorvmin in Leipzig. This was the first European publication to include all of the six standard trigonometrical ratios six hundred years after Islamic mathematics reached the same stage of development. Rheticus now dedicated his life to producing what would become the definitive work on trigonometrical tables his Opus palatinum de triangulis, however he died before he could complete and publish this work. It was finally completed by his student Valentin Otto (c. 1548–1603) and published in Neustadt and der Haardt in 1596.

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Source: Wikimedia Commons

In the meantime, Bartholomäus Piticus (1561–1613) had published his own extensive work on both spherical and plane trigonometry, which coined the term trigonometry, Trigonometria: sive de solution triangulorum tractatus brevis et perspicuous, one year earlier, in 1595.

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Source:. Wikimedia Commons

This work was republished in expanded editions in 1600, 1608 and 1612. The tables contained in Pitiscus’ Trigonometria were calculated to five or six places, whereas those of Rheticus were calculated up to more than twenty places for large angles and fifteenth for small ones. In comparison Peuerbach’s sine tables from the middle of the fifteenth century were only accurate to three places of decimals. However, on inspection, despite the years of effort that Rheticus and Otho had invested in the work, some of the calculations were found to be defective. Pitiscus recalculated them and republished the work as Magnus canon doctrinae triangulorum in 1607.

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He published a second further improved version under the title Thesaurus mathematicus in 1613. These tables remained the definitive trigonometrical tables for three centuries only being replaced by Henri Andoyer’s tables in 1915–18.

In the seventeenth century a major change in trigonometry took place. Whereas throughout the Renaissance it had been handled as a branch of practical mathematics, used to solve spherical and plane triangles in astronomy, cartography, surveying and navigation, the various trigonometrical ratios now became mathematical functions in their own right, a branch of purely theoretical mathematics. This transition mirroring the general development in the sciences that occurred between the Renaissance and the scientific revolution, from practical to theoretical science.

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Filed under History of Astronomy, History of Islamic Science, History of Mathematics, History of science, Renaissance Science

Alphabet of the stars

The brightest star in the night sky visible to the naked eye is Sirius the Dog Star. Its proper astronomical name is 𝛂 Canis Majoris. Historically for navigators in the northern hemisphere the most important star was the pole star, currently Polaris (the star designated the pole star changes over time due to the precession of the equinox), whose proper astronomical name is 𝛂 Ursae Minoris. The astronomical name of Sirius means that it is a star in the constellation in Canis Major, the greater dog, whilst Polaris’ name means that it is a star in Ursus Minor, the little bar. But what does the alpha that precedes each of these names mean and where does it come from?

A constellation consists of quite a large number of stars and this means that we need some sort of system of labelling or naming them for star catalogues, star maps or celestial atlases. The system that is used is the letters of the Greek alphabet. These are however not simply attached at random to some star or other but applied according to a system. That system was determined by apparent brightness.

Anybody who looks up into the night sky, when it is cloud free and there is no light pollution, will quickly realise that the various stars vary quite substantially in brightness. The ancient Greek astronomers were very much aware of this and divide up the stars into six categories, or as they are known magnitudes, according to their perceived or apparent brightness. Our unaided perception of the stars does not take into account their differing distances, so a very bright star that is very far away will appear less bright than not so bright star that is much nearer to the Earth. The earliest record of this six-magnitude scheme (one is the brightest, six the dimmest) is in Ptolemaeus’ Mathēmatikē Syntaxis, but it was probably older. The attribution, by some, to Hipparchus is purely speculative. Ptolemaeus also indicates intermediate values by writing greater than or less than magnitude X.

Using this basic framework inherited from Ptolemaeus, the early modern German astronomer Johann Bayer (1572–1625) labelled each of the stars in his maps of the constellations in his Uranometria (first published Augsburg, 1603) with a letter of the Greek alphabet, starting with alpha, in descending order of brightness, creating what is now known as the Bayer designation for stars. In this system the Greek letter is followed by a three-letter abbreviation of the constellation name. So, Aldebaran in the constellation Taurus is designated 𝛂 Tauri, abbreviated 𝛂 Tau. Who was Johann Bayer and what is the Uranometria?

Johann Bayer was born in Rain, a small town in Bavaria about forty kilometres north of Augsburg. He attended the Latin school in Rain and then probably a higher school in Augsburg.

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Rain by Matthäus Merian 1665 Source: Wikimedia Commons

He entered the University of Ingolstadt in 1592, where, having completed the foundation course, he went on to study law, graduating with a master’s degree around sixteen hundred. Leaving the university, he settled in Augsburg, where he worked as a lawyer until his death in 1625. The University of Ingolstadt had a strong tradition of the mathematical science over the preceding century, home to notable mathematicians and astronomers such as Johannes Werner, Johannes Stabius and Andreas Stiborius at the end of the fifteenth century and father and son Peter and Phillip Apian in the middle of the sixteenth. It was certainly here that Bayer acquired his love for mathematics and astronomy. He also acquired an interest in archaeology and would later in life take part in excavation in the Via Nomentana during a visit to Rome.

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Main building of the University of Ingolstadt 1571 Source: Wikimedia Comms

In 1603 Bayer’s Uranometria was published in Augsburg by Christophorus Mangus, or to give it its full title the Uranometria: omnium asterismorum continens schemata, nova methodo delineata, aereis laminis expressa. (Uranometria, containing charts of all the constellations, drawn by a new method and engraved on copper plates), that is a star atlas. The name derives from Urania the muse of astronomy, which in turn derives from the Greek uranos (oυρανός) meaning sky or heavens, it translates as “measuring the heavens” in analogy to “geometria”, measuring the earth.

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Title page of Uranometria Source: Wikimedia Commons

The Uranometria contains fifty-one star-maps engraved on copper plates by Alexander Mair (c. 1562–1617). The first forty-eight carts contain the northern-hemisphere constellations listed and described by Ptolemaeus. For the northern constellations Bayer used Tycho Brahe’s star catalogue, which hadn’t been published yet but was available through various sources. He, however, added one thousand more stars.

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Canis Major with Sirius very prominent on his nose Source

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Ursa Mino with Polaris on the end of his tail Source:

The forty ninth chart contains twelve southern-hemisphere constellations unknown to Ptolemaeus. Bayer took the star positions and constellation names for this southern-hemisphere chart from the 1597 celestial globe created by Petrus Plancius (1552–1622) of the observations collected for him by the Dutch pilot Pieter Dirkszoon Keyser (c. 1540–1596), which was printed by Jodocus Hondius (1563–1612).

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Chart of the Southern-Hemisphere ConstellationsSource

The final two charts are planispheres labelled Synopsis coeli superioris borea (Synopsis of the northern hemisphere) and Synopsis coeli inferioris austrina (Synopsis of the southern hemisphere).

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Synopsis coeli superioris borea Source

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Synopsis coeli inferioris austrina Source

For each star chart there is a star catalogue. In the first column the stars are listed according to their Ptolemaic number and then in their second column Bayer gives them the Bayer designation. Because the Greek alphabet only has twenty-four letters and some constellations have more than twenty-four stars, Bayer continues his list with the Latin alphabet using lower case letter except for the twenty-fifth star, which is designated with a capital A to avoid confusing a small with an alpha. The listing is not done strictly by order of brightness, listing the stars rather by the Ptolemaic magnitude classes. This means that by several constellations the star designated with an alpha is not actually the constellations brightest star.

Bayer was not the first astronomer to produce printed star maps in Europe (there are earlier printed Chinese star maps) that honour goes to the planispheres produced by Stabius, Dürer and Heinfogel in 1515.

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Dürer Northern Hemisphere Star Map Source: Wikimedia Commons

His was also not the first printed star atlas that being the Sfera del mondo e De le stelle fisse (The sphere of the world and the fixed stars) of Alessandro Piccolomini (1508–1579), both published in 1540 and often together. Piccolomini was an Italian humanist, philosopher and astronomer best known for his popularisations of Greek and Latin scientific treatises, which he translated into the vernacular.

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Portrait of Alessandro Piccolomini (1508-1579) engraving by Nicolas II de Larmessin Source: Wikimedia Commons

De le stelle fisse has charts of forty-seven of the Ptolemaic constellations, Equuleus (the little horse or foal) is missing. The book has a star catalogue organised by constellation, a series of woodblock plates of the constellations, tables indicating the stellar locations throughout the year and a section dealing with risings and settings of stars with reference to the constellations of the zodiac.

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However, unlike the Dürer planispheres and Bayer’s Uranometria, Piccolomini’s De le stelle fisse doesn’t have constellation figures.

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The book was very popular and went though, at least, fourteen editions during the sixteenth century. Piccolomini designated the stars in his catalogue with the letters of the Latin alphabet and there is the strong possibility that Bayer was inspired by Piccolomini in adopting his system of designation.

Bayer’s atlas was not free of problems. In the first edition the star catalogues were printed on the reverse of the constellation charts. This meant that it was not possible to consult the catalogue whilst viewing the chart. Also, the lettering of the catalogue showed through the page and spoiled the chart. To solve these problems the catalogue was printed separately in a smaller format under the title Explicatio charecterum aeneis Uranometrias in 1624, the year before Bayer’s death.

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It was republished in 1640, 1654, 1697 and 1723. Unfortunately, the Explicatio was marred by printing errors from the start, which got progressively worse with each new edition.

The Uranometria was republished often, and editions are known from in 1624, 1639, 1641, 1648, 1655, 1661, 1666 and 1689. It set standards for star atlases and planispheres and continued to influence the work of other star cataloguers down into the eighteenth century.The next time that a popular science programme on the telly or a science fiction story starts on about Alpha Centauri, the next closest star to our solar system, then you will know that this is the Bayer designation for a magnitude one, possibly the brightest, star in the constellation Centaurus, a centaur being the half man half horse creature from Greek mythology. It’s actually slightly more complex than Bayer believed because Alpha Centauri is now known to be a triple star system and is now designated α Centauri A (officially Rigil Kentaurus), α Centauri B (officially Toliman), and α Centauri C (officially Proxima Centauri).

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Uranometria Centaurus with Alpha Centauri on the near side front hoof Source

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Filed under History of Astrology, History of Astronomy, Renaissance Science

A flawed survey of science and the occult in the Early Modern Period

There is no shortage of good literature on the relationships between science and magic, or science and astrology, or science and alchemy during the Early Modern Period so what is new in Mark A. Waddell’s Magic, Science, and Religion in Early Modern Europe[1]? Nothing, because it is not Waddell’s aim to bring something new to this material but rather to present an introductory textbook on the theme aimed at university students. He sets out to demonstrate to the uninitiated how the seemingly contradictory regions of science, religion and magic existed in the Early Modern Period not just parallel to but interwoven and integrated with each other.  Waddell’s conception is a worthy one and would make for a positive addition to the literature, his book is however flawed in its execution.

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Image with thanks from Brian Clegg

The book actually starts well, and our author sets out his planned journey in a lengthy but clear and informative introduction. The book itself is divided into clear sections each dealing with a different aspect of the central theme. The first section deals with the Renaissance discoveries of hermeticism and the cabala and the concept of natural magic, as a force to manipulate nature, as opposed to demonic magic. Although limited by its brevity, it provides a reasonable introduction to the topics dealt with. My only criticisms concerns, the usual presentation of John Dee as a magus, whilst downplaying his role as a mathematician, although this does get mentioned in passing. However, Waddell can’t resist suggesting that Dee was the role model for Marlowe’s Faustus, whereas Faustus is almost certainly modelled on Historia von D. Johann Faustus, a German book containing legends about the real Johann Georg Faust (c. 1480–c. 1541) a German itinerant alchemist, astrologer, and magician of the German Renaissance. A note for authors, not just for Waddell, Dee in by no means the only Renaissance magus and is not the role model for all the literary ones.

Waddell’s second section deals with demonic magic, that is magic thought to draw its power from communion with the Devil and other lesser demons. As far as I can tell this was the section that most interested our author whilst writing his book. He manages to present a clear and informative picture of the period of the European witch craze and the associated witch hunts. He deals really well with the interrelationship between the belief in demonic witchcraft and the Church and formal religion. How the Church created, propagated and increasingly expanded the belief in demonic magic and witches and how this became centred on the concept of heresy. Communion with the devil, which became the central theme of the witch hunts being in and of itself heretical.

Following this excellent ´section the book starts to go downhill. The third section of the book deals with magic, medicine and the microcosm. Compared with the good presentation of the previous section I can only call this one a mishmash. We get a standard brief introduction to medieval academic medicine, which Waddell labels premodern, with Hippocrates, Galen and a nod to Islamic medical writes, but with only Ibn Sīnā mentioned by name. This is followed by a brief description of the principles of humoral medicine. Waddell correctly points out the academic or learned doctors only represent one group offering medical assistance during this period and gives a couple of lines to the barber-surgeons. It is now that the quality of Waddell’s presentation takes a steep nosedive.

Having correctly pointed out that medieval academic medicine was largely theoretical he then, unfortunately, follows the myth of “and then came Andy”! That is, we jump straight into Andreas Vesalius and his De fabrica, as I quote, “the beginnings of what we would understand as a rigorous and empirical approach to the study of anatomy.” Strange, only two weeks ago I wrote a post pointing out that Vesalius didn’t emerge out of the blue with scalpel raised high but was one step, albeit a very major one, in a two-hundred-year evolution in the study of anatomy. Of course, Waddell dishes up the usual myth about how seldom dissection was before Vesalius and corpses to dissect were rare etc, etc. Whereas, in fact, dissection had become a regular feature of medical teaching at the European universities over that, previously mentioned two-hundred-year period. Waddell closes his Vesalius hagiography with the comment that Vesalius’ De fabrica “was a crucial step in the more widespread reform of medical theory and practice that took place over the next 150 years” and although his book goes up to the middle of the eighteenth century, we don’t get any more information on those reforms. One of his final comments on Vesalius perpetuates another hoary old myth. He writes, “Vesalius made it permissible to question the legacy of antiquity and, in some cases, to overturn ideas that had persisted for many hundred years.” Contrary to the image created here, people had been challenging the legacy of antiquity and overturning ideas since antiquity, as Edward Grant put it so wonderfully, medieval Aristotelian philosophy was not Aristotle’s philosophy. The same applies to all branches of knowledge inherited form antiquity.

Having dealt with Vesalius, Waddell moves on to the philosophy of microcosm-macrocosm and astro-medicine or as it was called iatromathematics, that is the application of astrology to medicine. His basic introduction to the microcosm-macrocosm theory is quite reasonable and he then moves onto astrology. He insists on explaining that, in his opinion, astrology is not a science but a system of non-scientific rules. This is all well and good but for the people he is dealing with in the Early Modern Period astrology was a science. We then get a guide to astrology for beginners which manages right from the start to make some elementary mistakes. He writes, “You might know what your “sign” is, based on when you were born […]. These refer to the twelve (or according to some, thirteen) signs of the Western zodiac, which is the band of constellations through which the Sun appears to move over the course of a year.” The bullshit with thirteen constellations was something dreamed up by some modern astronomers, who obviously know nothing about astrology, its history or the history of their own discipline for that matter, in order to discredit astrology and astrologers. The only people they discredited were themselves. The zodiac as originally conceived by the Babylonians a couple of millennia BCE, mapped the ecliptic, the apparent annual path of the Sun around the Earth, using seventeen constellations. These were gradually pared down over the centuries until the Western zodiac became defined around the fifth century BCE as twelve equal division of the ecliptic, that is each of thirty degrees, starting at the vernal or spring equinox and preceding clockwise around the ecliptic. The most important point is that these divisions, the “signs”, are not constellations. There are, perhaps unfortunately, named after the constellations that occupied those positions on the ecliptic a couple of millennia in the past but no longer do so because of the precession of the equinoxes.

Although, Waddell gives a reasonable account of the basics of astro-medicine and also how it was integrated with humoral medicine but then fails again when describing its actual application. A couple of examples:

There were cases of surgeons refusing to operate on a specific part of the body unless the heavens were aligned with the corresponding zodiac sign, and it was not uncommon for learned physicians to cast their patient’s horoscope as part of their diagnosis.

[……]

Though the use of astrology in premodern medicine was common, it is less clear how often physicians would have turned to astrological magic in order to treat patients. Some would have regarded it with suspicion and relied instead on genitures alone to dictate their treatment, using a patient’s horoscope as a kind of diagnostic tool that provided useful information about that person’s temperament and other influences on their health. Astrological magic was a different thing altogether, requiring the practitioner to harness the unseen forces and emanations of the planets to heal their patient rather than relying solely on a standard regimen of care.

This is a book about the interrelationships between magic, religion and science during the Early Modern period, but Waddell’s lukewarm statements here, “there were cases of surgeons refusing to operate…, not uncommon for learned physicians…” fail totally to capture the extent of astro-medicine and its almost total dominance of academic medicine during the Renaissance. Beginning in the early fifteenth century European universities established the first dedicated chairs for mathematics, with the specific assignment to teach astrology to medical students.

During the main period of astrological medicine, the most commonly produced printed products were wall and pocket calendars, in fact, Gutenberg printed a wall calendar long before his more famous Bible. These calendars were astronomical, astrological, medical calendars, which contained the astronomical-astrological data that enabled physicians and barber-surgeons to know when they should or should not apply a particular treatment. These calendars were universal, and towns, cities and districts appointed official calendar makers to produce new calendars, every year. Almost no physician or barber-surgeon would consider applying a treatment at an inappropriate time, not as Waddell says, “cases of surgeons refusing to operate.” Also, no learned physicians in this time would begin an examination without casting the patient’s horoscope, to determine the cause, course and cure for the existing affliction. The use of what Waddell calls astrological magic, by which he means astrological talismans, by learned physicians was almost non-existent. This is aa completely different area of both astrology and of medicine.

Within the context of the book, it is obvious that we now turn to Paracelsus. Here Waddell repeats the myth about the name Paracelsus, “The name by which he is best known, Paracelsus, is something of a mystery, but historians believe that it was inspired by the classical Roman medical writer Celsus (c. 25 BCE–c. 50 CE). The prefix “para-“ that he added to that ancient name has multiple meanings in Latin, including “beyond,” leading some to speculate that this was a not-so-modest attempt to claim a knowledge of medicine greater than that of Celsus.” This is once again almost certainly a myth. Nowhere in his voluminous writings does Paracelsus mention Celsus and there is no evidence that he even knew of his existence. Paracelsus is almost certainly a toponym for Hohenheim meaning ‘up high’, Hohenheim being German for high home. By the way, he only initially adopted Paracelsus for his alchemical writings. The rest of his account of Paracelsus is OK but fails to really come to grips with Paracelsus’ alchemy.

To close out his section on medicine, Waddell now brings a long digression on the history of the believe in weapon salve, a substance that supposedly cured wounds when smeared on the weapon that caused them, an interesting example of the intersection between magic and medicine. However, he misses the wonderful case of a crossover into science when Kenhelm Digby suggested that weapon salve could be used to determine longitude.

 

The next section A New Cosmos: Copernicus, Galileo, and the Motion of the Earth, takes us into, from my point of view, a true disaster area:

In this chapter, we explore how the European understanding of the cosmos changed in the sixteenth and seventeenth centuries. It was on the single greatest intellectual disruptions in European history, and in some ways we are still feeling its effects now, more than 450 years later. The claim that our universe was fundamentally different from what people had known for thousands of years led to a serious conflict between different sources of knowledge and forms of authority, and forced premodern Europe to grapple with a crucial question: Who has the right to define the nature of reality?

This particular conflict is often framed by historians and other commentators as a battle between science and religion in which the brave and progressive pioneers of the heliocentric cosmos were attacked unjustly by a tyrannical and old-fashioned Church. This is an exaggeration, but not by much. [my emphasis]

Waddell starts with a standard account of Aristotelian philosophy and cosmology, in which he like most other people exaggerates the continuity of Aristotle’s influence. This is followed by the usual astronomers only saved the phenomena story and an introduction to Ptolemy. Again, the continuity of his model is, as usual, exaggerated. Waddell briefly introduces the Aristotelian theory of the crystalline spheres and claims that it contradicted Ptolemy’s epicycle and deferent model, which is simply not true as Ptolemy combined them in his Planetary Hypothesis. The contradiction between the two models is between Aristotle’s astronomical mathematical homocentric spheres used to explain the moments of the planets (which Waddell doesn’t mention), which were imbedded in the crystalline spheres, and the epicycle-deferent model. Waddell then hypothesises a conflict between the Aristotelian and Ptolemaic system, which simply didn’t exist for the majority, people accepting a melange of Aristotle’s cosmology and Ptolemy’s astronomy. There were however over the centuries local revivals of Aristotle’s homocentric theory.

Now Copernicus enters stage right:

Copernicus had strong ties to the Catholic Church; he was a canon, which meant he was responsible for maintaining a cathedral (the seat of a bishop or archbishop), and some historians believe he was ordained as a priest as well.

If a student writes “some historians” in a paper they normally get their head torn off by their teachers. Which historians? Name them! In fact, I think Waddell would have a difficult time naming his “some historians”, as all the historians of astronomy that I know of, who have studied the question, say quite categorically that there is no evidence that Copernicus was ever ordained. Waddell delivers up next:

Most probably it [De revolutionibus] was completed by the mid-1530s, but Copernicus was reluctant to publish it right away because his work called into question some of the most fundamental assumptions about the universe held at the time.

It is now generally accepted that Copernicus didn’t published because he couldn’t provide any proofs for his heliocentric hypothesis. Waddell:

He did decide to circulate his ideas quietly among astronomers, however, and after seeing his calculations were not rejected outright Copernicus finally had his work printed in Nuremberg shortly before his death.

Here Waddell is obviously confusing Copernicus’ Commentariolus, circulated around 1510 and  Rheticus’ Narratio prima, published in two editions in Danzig and Basel, which I wouldn’t describe as circulated quietly. Also, neither book contained  calculations. Waddell now tries to push the gospel that nobody really read the cosmological part of De revolutionibus and were only interested in the mathematics. Whilst it is true that more astronomers were interested in the mathematical model, there was a complex and intensive discussion of the cosmology throughout the second half of the sixteenth century. Waddell also wants his reader to believe that Copernicus didn’t regard his model as a real model of the cosmos, sorry this is simply false. Copernicus very definitely believed his model was a real model.

 Moving on to Tycho Brahe and the geo-heliocentric system Waddell tells us that, “[Tycho] could not embrace a cosmology that so obviously conflicted with the Bible. It is not surprising, then, that the Tychonic system was adopted in the years following Brahe’s death in 1601”

At no point does Waddell acknowledge the historical fact that also the majority of astronomers in the early decades of the seventeenth century accepted a Tychonic system because it was the one that best fit the known empirical facts. This doesn’t fit his hagiographical account of Galileo vs the Church, which is still to come.

Next up Waddell presents Kepler and his Mysterium Cosmographicum and seems to think that Kepler’s importance lies in the fact that he was ac deeply religious and pious person embraced a heliocentric cosmos. We then get an absolute humdinger of a statement:

There is more that could be said about Kepler, including the fact that he improved upon the work of Copernicus by proposing three laws of planetary motion that are still taught in schools today. For the purpose of this chapter, however, Kepler is significant as someone who embraced heliocentricity and [emphasis in the original] faith.

With this statement Waddell disqualifies himself on the subject of the seventeenth century transition from a geocentric cosmos to a heliocentric one. Kepler didn’t propose his three laws he derived them empirically from Tycho’s observational data and they represent the single most important step in that transition.

We now have another Waddell and then came moment, this time with Galileo. We get a gabled version of Galileo’s vita with many minor inaccuracies, which I won’t deal with here because there is much worse to come. After a standard story of the introduction of the telescope and of Galileo’s improved model we get the following:

[Galileo] presented his device to the Doge (the highest official in Venice) and secured a truly impressive salary for life from the Venetian state. Mere weeks later he received word from the court of the Medici in Galileo’s home in Tuscany, that they wanted a telescope of their own. The Venetian leaders, however had ordered Galileo to keep his improved telescope a secret, to be manufactured only for Venetian use, and Galileo obliged, at least temporarily.

When they bought Galileo’s telescope they thought, erroneously, that they were getting exclusive use of a spectacular new instrument. However, it soon became very clear that telescopes were not particularly difficult to make and were freely available in almost all major European towns. They were more than slightly pissed off at the good Galileo but did not renege on their deal. The Medici court did not request a telescope of their own, but Galileo in his campaign to gain favour by the Medici, presented them with one and actually travelled to Florence to demonstrate it for them. We now move on to the telescopic discoveries in which Waddell exaggerates the discovery of the Jupiter moons. We skip over the Sidereus Nuncius and Galileo’s appointment as court philosophicus and mathematicus in Florence, which Waddell retells fairly accurately. Waddell now delivers up what he sees as the great coup:

The problem was that the moons of Jupiter, while important, did not prove the existence of a heliocentric cosmos. Galileo kept searching until he found something that did: the phases of Venus.

The discovery of the phases of Venus do indeed sound the death nell for a pure geocentric system à la Ptolemy but not for a Capellan geo-heliocentric system, popular throughout the Middle Ages, where Mercury and Venus orbit the Sun, which orbits the Earth, or a full Tychonic system with all five planets orbiting the Sun, which together with the Moon orbits the Earth. Neither here nor anywhere else does Waddell handle the Tychonic system, which on scientific, empirical grounds became the most favoured system in the early decades of the seventeenth century.

We then get Castelli getting into deep water with the Grand Duchess Christina and, according to Waddell, Galileo’s Letter to the Grand Duchess Christina. He never mentions the Letter to Castelli, of which the Letter to the Grand Duchess Christina was a later extended and improved version, although it was the Letter to Castelli, which got passed on to the Inquisition and caused Galileo’s problems in 1615. Waddell tells us:

In 1616 the Inquisition declared that heliocentrism was a formal heresy.

In fact, the eleven Qualifiers appointed by the Pope to investigate the status of the heliocentric theory delivered the following verdict:

( i ) The sun is the centre of the universe (“mundi”) and absolutely immobile in local motion.

( ii ) The earth is not the centre of the universe (“mundi”); it is not immobile but turns on itself with a diurnal movement.

All unanimously censure the first proposition as “foolish, absurd in philosophy [i.e. scientifically untenable] and formally heretical on the grounds of expressly contradicting the statements of Holy Scripture in many places according to the proper meaning of the words, the common exposition and the understanding of the Holy Fathers and learned theologians”; the second proposition they unanimously censured as likewise “absurd in philosophy” and theologically “at least erroneous in faith”.

However, the Qualifiers verdict was only advisory and the Pope alone can official name something a heresy and no Pope ever did.

Waddell gives a fairly standard account of Galileo’s meeting with Cardinal Roberto Bellarmino in 1616 and moves fairly rapidly to the Dialogo and Galileo’s trial by the Inquisition in 1633. However, on the judgement of that trial he delivers up this gem:

Ultimately, Galileo was found “vehemently suspect of heresy,” which marked his crime as far more serious than typical, run-of-the-mill heresy.

One really should take time to savour this inanity. The first time I read it, I went back and read it again, because I didn’t think anybody could write anything that stupid. and that I must have somehow misread it. But no, the sentence on page 131 of the book reads exactly as I have reproduced it here. Maybe I’m ignorant, but I never knew that to be suspected of a crime was actually “far more serious” than actually being found guilty of the same crime. One of my acquaintances, an excellent medieval historian and an expert for medieval astronomy asked, “WTF is run-of-the-mill heresy?” I’m afraid I can’t answer her excellent question, as I am as perplexed by the expression, as she obviously is.

Enough of the sarcasm, the complete sentence is, of course, total bollocks from beginning to end. Being found guilty of suspicion of heresy, vehement or not, is a much milder judgement than being found guilty of heresy. If Galileo had been found guilty of heresy, there is a very good chance he would have been sentenced to death. The expression “run-of-the-mill heresy” is quite simple total balderdash and should never, ever appear in any academic work.

Waddell now draws his conclusions for this section, and they are totally skewed because he has simple ignored, or better said deliberately supressed a large and significant part of the story. In the final part of this section, “Science versus Religion?”, he argues that the Church was defending its right to traditional truth against Galileo’s scientific truth. He writes:

This was not a fight between winners and losers, or between “right” and “wrong.” Instead, this is a story about power, tradition, and authority, about who gets to decide what is true and on what grounds.

[……]

Organised religion, exemplified here by the Catholic Church, had an interest in preserving the status quo [emphasis in original] for many reasons, some of which were undeniably self-serving.

[……]

The ideas of Aristotle and Ptolemy were still taught in virtually every European university well into the seventeenth century, making the Church’s allegiance to these ideas understandable. At the same time, the Church also recognised another source of authority, the Christian scriptures, which stated clearly that the Earth did not move. On both philosophical and theological grounds, then, the Church’s position on the immobility of the Earth was reasonable by the standards of the time.  

The above quotes have more relationship to a fairy tale than to the actual historical situation. Due to the astronomical discoveries made since about 1570, by1630 the Catholic Church had abandoned most of the Aristotelian cosmology and never adopted  Aristotelian astronomy. They fully accepted that the phases of Venus, almost certainly observed by the Jesuit astronomers of the Collegio Romano before Galileo did, refuted the Ptolemaic geocentric astronomy. Instead by 1620 the Church had officially adopted the Tychonic geo-heliocentric astronomy, not, as Waddell claims, on religious grounds but because it best fit the known empirical facts. Despite efforts since 1543, when Copernicus published De revolutionibus, nobody, not even Galileo, who had tried really hard, had succeeded in finding any empirical evidence to show that the Earth moves. Waddell’s attempt to portrait the Church as at best non-scientific or even anti.scientific completely ignores the fact that Jesuit and Jesuit educated mathematicians and astronomer were amongst the best throughout the seventeenth century. They made significant contributions to the development of modern astronomy before the invention of the telescope, during Galileo’s active period, in fact it was the Jesuits who provided the necessary scientific confirmation of Galileo’s telescopic discoveries, and all the way up to Newton’s Principia. Their record can hardly be described as anti-scientific.

The Church’s real position is best summed up by Roberto Bellarmino in his 1615 letter to Foscarini, which is also addressed to Galileo:

Third, I say that if there were a true demonstration that the sun is at the centre of the world and the earth in the third heaven, and that the sun does not circle the earth but the earth circles the sun, then one would have to proceed with great care in explaining the Scriptures that appear contrary; and say rather that we do not understand them than that what is demonstrated is false. But I will not believe that there is such a demonstration, until it is shown me. 

Put simple prove your theory and we the Church will then reinterpret the Bible as necessary, which they in fact did in the eighteenth century following Bradley’s first proof that the Earth does actually move.

Waddell then goes off on a long presentist defence of Galileo’s wish to separate natural philosophy and theology, which is all well and good but has very little relevance for the actual historical situation. But as already stated, Waddell is wrong to claim that the phases of Venus prove heliocentrism. Worse than this Galileo’s Dialogo is a con. In the 1630s the two chief world systems were not Ptolemy and Copernicus, the first refuted and the second with its epicycle-deferent models, which Galileo continues to propagate, abandoned, but the Tychonic system and Kepler’s ecliptical astronomy, which Waddell like Galileo simply chose to ignore.

One last comment before I move on. Somewhere Waddell claims that Galileo was the first to claim that the Copernicus’ heliocentric model represented reality rather than simply saving the phenomena. This is historically not correct, Copernicus, Tycho and Kepler all believed that their models represented reality and by 1615, when Galileo first came into confrontation with the Church it had become the norm under astronomers that they were trying to find a real model and not saving the phenomena.

Waddell’s account of the early period of the emergence of modern astronomy sails majestically past the current historical stand of our knowledge of this phase of astronomical history and could have been written some time in the first half of the twentieth century but should not be in a textbook for students in the year 2021.

With the next section we return to some semblance of serious state-of-the-art history. Waddell presents and contrasts the mechanical philosophies of Pierre Gassendi and René Descartes and their differing strategies to include their God within those philosophies. All pretty standard stuff reasonably well presented. The section closes with a brief, maybe too brief, discourse on Joseph Glanvill’s attempts to keep awareness of the supernatural alive against the rationalism of the emerging modern science.

The penultimate section deals with the transition from the Aristotelian concept of an experience-based explanation of the world to one based on experiments and the problems involved in conforming the truth of experimental results. In my opinion he, like most people, gives far too much attention/credit to Francis Bacon but that is mainstream opinion so I can’t really fault him for doing so. I can, however, fault him for presenting Bacon’s approach as something new and original, whereas Bacon was merely collating what had been widespread scientific practice for about two centuries before he wrote his main treatises. Specialist historians have been making this public for quite some time now and textbooks, like the one Waddell has written, should reflect these advances in our historical awareness.

Waddell moves on to alchemy as another source of experimentation that influenced the move to an experiment-based science in the seventeenth century. To be honest I found his brief account of alchemy as somewhat garbled and meandering, basically in need of a good editor. He makes one error, which I found illuminating, he writes:

Aristotle in particular had taught that all metals were composed of two principles: Mercury and Sulphur

Aristotle thought that metals were composed of two exhalations, one is dry and smoky, the other wet and steamy. These first became widely labeled as Mercury and Sulphur in the ninth century writings of the Arabic alchemist Jābir ibn-Hayyān, who took it from the mid-ninth century work, the Book of the Secrets of Creation by Balīnūs. I find this illuminating because I don’t know things like this off by heart, I just knew that Mercury-Sulphur was not from Aristotle, and so have to look them up. To do so I turned to Principe’s The Secrets of Alchemy. Now, according to Waddell’s bibliographical essays at the end of the book, Principe is his main source for the history of alchemy, which means he read the same paragraph as I did and decided to shorten it thus producing a fake historical statement. When writing history facts and details matter!

Having introduced alchemy we now, of course, get Isaac Newton. Waddell points out that Newton is hailed as the epitome of the modern scientist, whereas in fact he was a passionate exponent of alchemy and devoted vast amounts of time and effort to his heterodox religious studies. The only thing that I have to criticise here is that Waddell allocates Newton and his Principia to the mechanical philosophy, whereas his strongest critics pointed out that gravity is an occult force and is anything but conform with the mechanical philosophy. Waddell makes no mention of this here but strangely, as we will see does so indirectly later.

The final section of the book is a discussion of the enlightenment, which I found quite good.  Waddell points out that many assessments of the enlightenment and what supposedly took place are contradicted by the historical facts of what actually happened in the eighteenth century.

Waddell draws to a close with a five-page conclusion that rather strangely suddenly introduces new material that is not in the main text of the book, such as Leibniz’s criticism that Newton’s theory of gravity is not mechanical. It is in fact more a collection of after thoughts than a conclusion.

The book ends with a brief but quite extensive bibliographical essay for each section of the book, and it was here that I think I found the reason for the very poor quality of the A New Cosmos section, he writes at the very beginning:

Two important studies on premodern astronomy and the changes it experienced in early modern Europe are Arthur Koestler’s The Sleepwalkers: A History of Man’s Changing Vision of the Universe (Penguin Books, 1990) and Thomas Kuhn’s The Copernican Revolution: Planetary Astronomy in the Development of Western Thought (Harvard University Press, 1992)

The Sleepwalkers was originally published in 1959 and The Copernican Revolution in 1957, both are horribly outdated and historically wildly inaccurate and should never be recommended to students in this day and age.

All together Waddell’s tome  has the makings of a good and potentially useful textbook for students on an important set of themes but it is in my opinion it is spoilt by some sloppy errors and a truly bad section on the history of astronomy in the early modern period and the conflict between Galileo and the Catholic Church.

[1] Mark A. Waddell, Magic, Science, and Religion in Early Modern Europe, Cambridge University Press, Cambridge & London, 2021

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Filed under Book Reviews, History of Alchemy, History of Astrology, History of Astronomy, History of medicine, History of science, Renaissance Science

Review of a book I have not read and have absolutely no intention of wasting money on!

Since this blog post was written, Professor Screech has recognised and acknowledged that he erred in his book and has made changes in the text reflecting the criticism in this post, which are already in the ebook version and will soon appear in a new print edition. To what extent he has made changes, I cannot at the moment say, but I shall be receiving a print copy of the amended book and will report when I have read it. The OUP blog post discussed here has already been amended.

Timon Screech is an art historian, who is professor for Japanese art of the Early Modern Period at SOAS in London. He is the author of numerous books and in his newest publication has decided to turn his hand to the history of astronomy at the beginning of the seventeenth century, namely the early years following the invention of the telescope, the result is a train wreck! The offending object is, The Shogun’s Silver Telescope: God, Art and Money in the English Quest for Japan, 1600–1625. OUP, 2020.

9780198832034

If, as I state in the title to this blog post, I have not read this book, and in fact have no intentions of wasting my time and money in doing so, how can I claim that it is a train wreck? OUP have been kind enough to provide a description of the book on the Internet and Professor Screech has posted a lecture on YouTube in which he elucidates the central thesis of his work. These contain enough statements that make it very clear that that central thesis is a festering heap of dodo dung.

The OUP description opens thus:

Over the winter of 1610-11, a magnificent telescope was built in London. [my emphasis] It was almost two metres long, cast in silver and covered with gold. This was the first telescope ever produced in such an extraordinary way, worthy of a great king or emperor. Why was it made and who was it going to?

The origins of telescopes are shrouded in mystery. All that is known for sure is that the first one to be patented had been built in Middleburgh, in the Dutch Republic, in October 1608. [my emphasis] The English were soon making their own under the name of “prospective glasses,” for seeing “prospects” or distant views. One had been shown to King James I of England and Scotland in May 1609. The English and Dutch were not alone, for, famously, Galileo obtained a telescope some months later and conducted experiments in Venice. In March 1610, he published his seminal study, The Starry Messenger (so-called in English, though the text is in Latin). King James’s ambassador to Venice sent a copy to the king post-haste, with a letter emphasising the extraordinary importance of the object.

The telescope in question was very probably not built in London but imported from Holland, as was the one shown to James I&VI in 1609. The origins of the telescope, whilst complex, are, of course, not shrouded in mystery; there is in fact quite a lot of very good historical research on the subject. The Dutch city, where Hans Lipperhey (1569–1619) made the telescope mentioned in the next sentence lived, is Middelburg and not Middleburgh, which apparently is a town in the State of New York. Now history is not an exact academic discipline but an interpretative one. From the usually limited facts available the historian tries their best to recreate as accurately as possible that part of the past he is dealing with. Important in this process is that they get the known facts right. We know from that historical research on the origins of the telescope that Lipperhey applied to the States General for a patent for his instrument in Den Hague on 2 October 1608. However, we also know that on 15 December 1608 his request for a patent was denied. Actually, Sir Henry Wotton the English ambassador to Venice sent two copies of Galileo’s Sidereus Nuncius to London on the day it was published, 12 March 1610.

Up till now the OUP’s account has only been inaccurate and sloppy but now they leave the realm of bad history and enter the world of fantasy or perhaps wishful thinking

The telescope built in London the next year was made for King James I. It was not his to keep but was to be sent in his name to one of the world’s supreme potentates—one the English were desperate to please. This was the Shogun of Japan, Tokugawa Ieyasu.

Why send a telescope? English trade with Asia was the monopoly of the East India Company, founded a decade before, and they were very anxious to open markets in Japan. It was with a telescope that Galileo had made his findings, and although his discoveries were received with enthusiasm in some quarters, this was not the case in others. The Papacy, famously, could not accept his key finding, namely that the earth orbits the sun— [my emphasis] heliocentricity contradicted Scripture, which states that the sun moves. Later Galileo would be summoned before the Inquisition for this, as telescopes became a central battleground between Rome and the Protestant churches. [my emphasis] It had evidently dawned on the East India Company, and perhaps on King James himself, that here was the perfect a way to court Japanese favour. They would show the shogun the latest scientific instrument, and in doing so embarrass the Iberians. Spain and Portugal were already trading successfully in Japan, accompanied by Jesuit missionaries, to whom the English had the highest aversion: the Jesuits were blamed for many things, including Guy Fawkes and the Gunpowder Plot of 1605. In Japan, they spent as much time teaching astronomy as theology. A telescope would prove that they were teaching falsehoods, and that the Jesuits were a danger to Japan. [my emphasis]

First up, we have the usual false claim about the Sidereus Nuncius that it provided proof of the heliocentric hypothesis, it didn’t, and Galileo knew well that it didn’t. As a historian one gets tired of busting the same myths over and over again, but once more for those who haven’t been paying attention. The new telescopic discoveries made by 1610, not just by Galileo, disproved two aspects of Aristotelian cosmology, that the heavens were perfect and celestial bodies perfect spheres, and that all celestial bodies orbit a common centre. However, it offered no evidence to truly support or refute any of the three main contending models of the cosmos, geocentricity, heliocentricity and geo-heliocentricity. The later discovery of the phases of Venus eliminated a pure geocentric model, but that was made public well after the Shogun shiny new telescope was on its way to Japan, so needn’t be considered here.

I have looked at the phrase, as telescopes became a central battleground between Rome and the Protestant churches numerous times, from various standpoints and different angles and all that occurs to me is, what the fuck is that supposed to mean? It is simply put baloney, balderdash, poppycock, gibberish, hogwash, drivel, palaver, mumbo jumbo, rubbish, or even more simply, total and utter crap! I’m not even going to waste time, space and effort in trying to analyse and refute it, it doesn’t deserve it. Somebody please flush it down the toilet into the sewers, where it belongs.

The final emphasised sentence is the whole crux of Screech’s argument, as we shall see, it refers to the fact that the Jesuit astronomers in Japan in 1611 were teaching that the cosmos was geocentric, as this was certainly the accepted scientific view of the vast majority of European astronomers in 1611, including those in London, I think claiming that they were teaching falsehoods is historically simply wrong.

OUP now explain how the telescope was delivered to the Shogun in Japan and make a clear statement of Screech’s central thesis:

The telescope was taken out in a flotilla of four vessels in spring 1611. Command was given to John Saris, who had already lived several years in Asia, as the most senior English merchant. Now on his second trip East, he was told to push further on, all the way to Japan, where no English ship had yet gone. Oddly, the Company was aware of one Englishman already living in Japan. This was William Adams, who had gone on a Dutch ship. Many people in London remembered him, and word was that he had married a great Japanese lady. Saris took only one of his ships to Japan (the others went home with nearer Asian goods), arriving in Japan in summer 1613. Adams was contacted and within a few months he and Saris took the telescope to the Shogun’s castle, presenting it together in September at a grand ceremony. The Japanese records show to this. Saris enjoyed success in opening trade with Japan, and by December 1614 was safely back in London. Adams preferred to stay.

Once the English had provided proof that “European astronomy,” as explained in Japan for many years, was all wrong, the Roman Catholic missions lost their value. [my emphasis] They were closed down forthwith, and the Jesuit missionaries were expelled. Their old enemies put to flight, the English looked forward to unfettered trade with what was perhaps the world’s richest country, somewhat grudgingly agreeing to share this with the Dutch.

You will be amazed as to how John Saris provided proof that “European astronomy,” as explained in Japan for many years, was all wrong.

We now turn to our author’s own presentation of his thesis in a 45-minute YouTube video. I shall only be commenting on the relevant statements from this.

(starting at approx. 23 mins) In 1610 Galileo had conducted his extraordinary discoveries.

Actually, he made a large part of them in 1609, he published them in 1610.

The first telescope referred to in England is also in 1609, when one was shown to King James.…We also know that one was on public display in London shortly after the Clove [Saris’ ship] left England [1611] In other words they are still very rare, very special things. Not that many people can get hold of them.  

Screech is obviously not aware of the fact that Thomas Harriot had been making and using telescopes in London since 1609 and by 1611, the group centred on Harriot (Harriot, Christopher Tooke his lens grinder, Sir William Lower and John Prydderch (or Protheroe)) were making and comparing astronomical observation. In fact, Harriot was using telescopes before Galileo.

Even in 1618, a telescope is still a rather unusual thing

Sorry, but no it wasn’t, not in scientific circles

The Japanese record says something that the English record doesn’t say that the telescope was, using their own measurements, about ten feet long. So, it was extremely long and that must have meant that it was actually quite powerful. Possibly more powerful than the one Galileo used. It was two years later so lenses might have improved. Galileo could of course see the rings of Saturn with his.  

There is quite a lot to unpack here, which illustrates that Screech actually knows nothing about the early history of the telescope. For a telescope in 1611, ten feet is quite long not extremely long, telescopes later in the century reached lengths of fifty and sixty feet. However, length does not equal magnification power. For a Dutch or Galilean telescope, the magnification equals the focal length of the objective lens divided by the focal length of the eyepiece lens. So, if the Shogun’s telescope’s objective had a focal length of 120 inches and the eyepiece one of 1 inch, then it would have a magnification of 120. However, if the objective focal length was 8 feet and the eyepiece one 2 feet, its magnification would be only 4. These are not real numbers, just illustrative examples.

Galileo had a four-foot telescope with a magnification of c. 30, meaning an objective with focal length of c. 46.5 inches and an eyepiece focal length of c. 1.5 inches. The next problem is the higher the magnification of a Dutch telescope the smaller the field of vision. A magnification of about 30 is the upper limit for a usable Dutch telescope, anything above that is basically useless. Galileo made most of his discoveries with a telescope with a magnification of about 20. There was also no real improvement in lens making between 1609 and 1611. The telescope delivered to the Shogun was almost certainly of poorer quality than those used by Galileo, who was at the time producing some of the best lenses in Europe. 

The telescope is then presented and Ieyasu and Adams have a big discussion about and about what it means and what did it mean? Galileo, of course, as we all know ran into big problems with the Church, not because he discovered the rings of Saturn, which they didn’t care very much about but because he discovered that the Earth is not the centre of the world.  [my emphasis] Church history, of course, early Ptolemaic astronomy teaches that the Earth is the centre of the world and the Sun revolves around it, which obviously you would think standing on Earth and watching the Sun move. We still say the Sun rises and sets and goes by the clouds. We use these expressions today although they are, of course, astronomical completely incorrect. So, the Church had a problem because the Bible explicitly says that the Sun moves, and you can’t suddenly say that it doesn’t.

The Catholic Church took a great interest in astronomy and Catholic astronomers, many of them Jesuits or Jesuit trained, took a great interest in all of Galileo’s discoveries including the indecipherable something that later turned out to be the rings of Saturn. Galileo, of course, did not then or at any later time discover that the Earth is not the centre of the world. The conflict between the Bible and the heliocentric hypothesis did not became an issue for the Church before 1615!

Now, the Church didn’t care too much about this because heliocentricity was an extremely abstruse thing. Copernicus was even a Roman Catholic priest and he did his discoveries while living with a Roman Catholic bishop in Poland. But Copernicus book has been called the book that nobody ever read, if you get hold of a copy it’s impossible to read it’s in Latin, it’s completely impossible to understand. So, Copernicus’s discovery of heliocentricity had not really bothered anyone. The thing about the telescope is that any person using a telescope can see for themselves that heliocentricity is correct. This would give the Church considerable worries and that’s why they…it was Galileo pulled before the Inquisition; Copernicus had died peacefully in bed. [my emphasis]

Before I start to dismantle it, one should reflect that this heap of garbage was written by a professor for history at a world-famous institute for higher education. I weep. I’m almost ashamed to admit that my father taught history at the same institution.

Where to start? We start with a couple of simple facts. There is nothing abstruse about the heliocentric hypothesis and Copernicus was not a Roman Catholic priest. He was a canon of the Cathedral of Frombork, who never took holy orders. I do hope that Owen Gingerich doesn’t see this video. The expression the book that nobody read is a quote from Arthur Koestler’s popular history of astronomy, The Sleepwalkers. Gingerich spent several decades searching out all the extant copies of the first and second editions of Copernicus’ De revolutionibus and analysing the readers’ annotations and marginalia to show that an awful lot of people did read it and did so meticulously. He published the results of his long year endeavours in his, An Annotated Census of Copernicus’ De Revolutionibus (Brill, 2002), a very useful reference book for historians of astronomy. He then published an entertaining autobiographical book detailing some of the adventures he experienced compiling his census, The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus (Walker & Company, 2004). There was of course a very lively discussion about De revolutionibus and the heliocentric hypothesis amongst European astronomers between its publication in 1543 and 1611. If Professor Screech is too lazy to plough his way through Gingerich’s Census then might I suggest he reads, Pietro Daniel Omodeo, Copernicus in the Cultural Debates of the Renaissance: Reception, Legacy, Transformation (Brill, 2014) & Jerzy Dobrzycki ed., The Reception of Copernicus’ Heliocentric Theory (D Reidel, 1972). He might actually learn something.

Once again, I find myself flabbergasted by a Screech statement, if you get hold of a copy it’s impossible to read it’s in Latin, it’s completely impossible to understand. This man is an academic historian or at least so he claims. Of course, it’s in bloody Latin that was the academic language of communication in the sixteenth century that all professional astronomers used. Also, for a sixteenth century astronomer the book is perfectly understandable.

Once again Screech takes us into cloud cuckoo land, The thing about the telescope is that any person using a telescope can see for themselves that heliocentricity is correct. I have to ask, when looking through this magic telescope, did the observer see little green Martians holding up a neon sign reading, you are now viewing a heliocentric cosmos? It would be 182 years after the publication of De revolutionibus and 117 after the invention of the telescope before somebody was able, using a telescope, to prove that the Earth orbits the Sun, when in 1725 Molyneux and Bradley detected stellar aberration, delivering the first real empirical evidence for heliocentricity. Empirical evidence for diurnal rotation would first come 126 years later, when Foucault demonstrated his pendulum in 1851!

Screech seems to have problems with chronology; he writes, This would give the Church considerable worries and that’s why they…it was Galileo pulled before the Inquisition; Copernicus had died peacefully in bed. Screech’s story takes place between 1611 and 1613. Galileo’s first run in with the Church, concerning heliocentricity, was in 1615/16 and he was first “pulled” before the Inquisition in 1633.

So, the English had clearly turned up with an object, which was a wonderful thing to see in its own right, but it will also confuse and embarrass the Roman Catholic Church [my emphasis].

No, it wouldn’t! 

And this is where Spain and Portugal come in, hopefully the present given by the king will neutralise the Dutch and show that the English were better than the Dutch but the Spanish and the Portuguese had been there much longer than the Dutch had been there for decades and most of the Spanish are buying and selling, are merchants. But, of course, there are a large number of priests, and the merchants tend to stick to the ports because that’s where they do business but the priest wander all over the place and the priest had had this absolute dream of building a church in Kyoto, which was the capital city at the time, and they had succeeded in doing it.  […] Of course, the missionaries mostly Jesuits […] where seeking conversions. […] But the Jesuits also taught in Japan astronomy and this was absolutely crucial because various Japanese rituals surrounding the court and not the Shogun but the actual Emperor of Japan, it was very important to predict eclipses. This is really key to Japanese political thinking, and over the course of a lunar calendar that went out of sync Japanese astronomers had become less and less able to predict eclipses and the Jesuits could do it. This was also a reason why Christian missions were accepted in China, not to teach the gospel but to teach astronomy. [my emphasis]

I admit, quite freely, that I know nothing about Japanese astronomy in the Early Modern Period, but I do know that this was the function that the Jesuits fulfilled in China in the seventeenth century, which gave them access to Chinese society at the highest levels. They even ran the Chinese office or ministry for astronomy for large parts of that century. This being the case I assume that Screech is correct in saying the same for Japan.

The English had suddenly turned up and they say to the Japanese, all that astronomy they’ve been teaching you for the last fifty years, telling you how important it is, it’s wrong. It’s not only wrong, they know its wrong and they’re teaching you lies. And this must have been what Ieyasu heard in those hours after Saris left the room, while he has in his hands his silver telescope. [my Emphasis]

Just exactly how did the English tell Ieyasu this? As I have already pointed out, he could not have possibly got this information simply by looking through the telescope, as Screech claims, this is pure bullshit.  Screech has obviously never tried to observe the heavens with a replica of an early seventeenth century Dutch or Galilean telescope. If you have never ever used one, and Ieyasu very obviously hadn’t, the very small field of vision means that you see almost nothing. If you are trying to use one without a tripod or some other support, then every slightest tremor of your hand or arms sends the image skittering across the skies. Even worse for Ieyasu, early telescopes suffered from both spherical and chromatic aberration meaning that the image was blurred and had coloured fringes. Add to this that early lenses were of very poor quality and so the images were anything but good and you’re not really going to impress anybody. Almost certainly. Saris and Adams demonstrated the telescope as a terrestrial telescope, as had Lipperhey during his first demonstration in Den Hague in the last September week in 1608.  So, what about Saris and Adams as a source of astronomical information. Saris was a merchant trader and not an astronomer and there is nothing to indicate that he would have been up to date on the actual astronomical/cosmological discussions, let alone that he would have been a, for that time rare, supporter of heliocentricity. Adams is even more unlikely to have been informed of all things astronomical. He had been living in Japan since 1600, so the telescope would have been just as much a novelty for him as it was for Ieyasu. He was however a navigator so he would have had a basic knowledge of astronomy. However, navigators, even today learn geocentric astronomy, so once again no information forthcoming from that quarter.

Saris was given as a result of this permission to open a trading station in Japan and Ieyasu even said you can trade anywhere in my dominions that you wish. […]

Saris sailed back to England at the end of 1613 […] Within months, actually within weeks, even possibly within days of Saris leaving Ieyasu issues an instruction all Jesuit churches must be torn down all priests must leave the country and there was tremendous destruction. And in the early months of 1614 running through into the autumn, was what is often known as the great exile as a vast number of Japanese Christians fled. Mostly they went to the Philippines under Spanish protection or they went to Goa under Portuguese protection. We don’t know the number involved probably in the thousands. Fifty or sixty priest and friars left too […]

Why did it happen then, the Spanish and the Portuguese had been in Japan for fifty year and suddenly in one winter they were told to leave because the English turned up with their telescope.

Screech has turned a correlation into a cause and effect, with a fallacious chain of reasoning based on a series of falsehoods. Analysed rationally the whole argument falls together like a house of cards that was erected with soggy sheets of toilet paper. If we add some more astronomical and historical context then Screech’s whole heap of fact vacant waffle collapses even further.

 Screech informs us that the Japanese, like the Chinese, were interested in the Jesuit’s knowledge of astronomy because of their ability to accurately predict eclipses, which in Asian culture had a massive socio-political and cultural significance. What Screech doesn’t appear to know is that eclipse prediction models are, by nature, fundamentally geocentric as they are based on the relative positions of the Sun and Moon on the ecliptic, the Sun’s apparent path around the Earth. So, the revelation that the solar system is heliocentric and not geocentric, would in this case have no relevance whatsoever.

Next, it pays to take a look at the Jesuits, the early history of the telescope and Asia. Would they have feared, or did they fear the revelations of the telescope? Historically the exact opposite is the case. The Jesuit astronomers of the Collegio Romano, were making telescopic astronomical observations at least as early as Galileo and it was these astronomers, working together with Galileo, who provided the very necessary scientific confirmation of all of his discoveries. Having done so, they threw a large banquet in his honour in Rome. This doesn’t quite fit Screech’s narrative but there is more.

Almost all the telescopes, with possibly only the exception of King James’ present for Ieyasu, introduced into Asia,–India, China and even Japan–in the early part of the seventeenth century were brought there by the Jesuit missionaries. Mainly, like the silver telescope, as presents to impress but also for their own astronomical work. Jesuit missionaries bound for Asia were prepared for their mission at the University of Coimbra in Portugal. We know that from 1615 to 1617 the Jesuit astronomer, Giovanni Paolo Lembo (1570–1618), one of those Collegio Roman astronomers who confirmed Galileo’s discoveries, not only taught those trainee missionaries astronomy but also lens grinding and telescope construction, to enable them to make their own instruments in Asia. The Jesuits were also the first to introduce the heliocentric hypothesis into Asia, which they did in China, in Chinese, during the course of the seventeenth century.

Having completely demolished Screech’s totally crackbrained thesis, could there be another reason why the Jesuits were expelled from Japan shortly after the arrival of the English traders, apart from pure coincidence?

What Screech doesn’t explain in his lecture, maybe he does in his book, but I doubt it, is that there had been serious stress between the Jesuits and the rulers of Japan for several years before the arrival of the English. Toyotomi Hideyoshi, who unified Japan in the mid 1580s was suspicious of the activities of the Catholics and in 1587 he banned Catholicism in Japan. In 1597 twenty-six Christians–six Franciscan missionaries, three Japanese Jesuits and seventeen Japanese laymen–were crucified. Toyotomi Hideyoshi died in 1598 and was succeeded by Tokugawa Ieyasu, who also distrusted the Catholics but wished to trade with both Spain and Portugal. The Protestant Dutch provided a counterbalance, so that the Iberian Catholics did not have a trade monopoly. The arrival of the English in 1613, meant that Ieyasu now had two Protestant European trading partners, who would compete because they didn’t like each other, but who both promised not to try and convert the Japanese to Christianity. Ieyasu could now get rid of the despised Catholics, which he then did in 1614. Simple, factual historical explanation without a cock and bull story about a magical telescope that revealed the heliocentric nature of the cosmos when one simply looked through it.

I find it both fascinatingly gruesome but also frightening and ultimately very depressing that a professor of history from a world-renowned university can propagate a thesis based on the early history of the telescope and the history of the most important transition in the history of astronomy, apparently without bothering to learn anything about either discipline. It appears that his sources were something along the lines of the 1920s Boy’s Own Big Book: Galileo’s Persecution by the Nasty Catholics and Enid Blyton’s Guide to the History of Astronomy for Under Fives.

Screech’s only achievement is that with his, The thing about the telescope is that any person using a telescope can see for themselves that heliocentricity is correct, he delivers one of the mind bogglingly stupid history of science statements that I have ever read.

 The main thesis of his book, which he presents in the lecture analysed here, is an abomination and an insult to every historian of the telescope and/or astronomy. Even worse is the fact that OUP, a major academic publisher, published and are promoting this heap of crap, without having subjected it to any sort of control of the accuracy of its historical content. If OUP possessed even a shred of decency, they should withdraw this book from the market, pulp it and issue a public apology to the history of science community.

 

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Filed under Book Reviews, History of Astronomy

The emergence of modern astronomy – a complex mosaic: Part LII

This is a concluding summary to my The emergence of modern astronomy – a complex mosaic blog post series. It is an attempt to produce an outline sketch of the path that we have followed over the last two years. There are, at the appropriate points, links to the original posts for those, who wish to examine a given point in more detail. I thank all the readers, who have made the journey with me and in particular all those who have posted helpful comments and corrections. Constructive comments and especially corrections are always very welcome. For those who have developed a taste for a continuous history of science narrative served up in easily digestible slices at regular intervals, a new series will start today in two weeks if all goes according to plan!

There is a sort of standard popular description of the so-called astronomical revolution that took place in the Early Modern period that goes something liker this. The Ptolemaic geocentric model of the cosmos ruled unchallenged for 1400 years until Nicolas Copernicus published his trailblazing De revolutionibus in 1453, introducing the concept of the heliocentric cosmos. Following some initial resistance, Kepler with his three laws of planetary motion and Galileo with his revelatory telescopic discoveries proved the existence of heliocentricity. Isaac Newton with his law of gravity in his Principia in 1687 provided the physical mechanism for a heliocentric cosmos and astronomy became modern. What I have tried to do in this series is to show that this version of the story is almost totally mythical and that in fact the transition from a geocentric to a heliocentric model of the cosmos was a long drawn out, complex process that took many stages and involved many people and their ideas, some right, some only half right and some even totally false, but all of which contributed in some way to that transition.

The whole process started at least one hundred and fifty years before Copernicus published his magnum opus, when at the beginning of the fifteenth century it was generally acknowledged that astronomy needed to be improved, renewed and reformed. Copernicus’ heliocentric hypothesis was just one contribution, albeit a highly significant one, to that reform process. This reform process was largely triggered by the reintroduction of mathematical cartography into Europe with the translation into Latin of Ptolemaeus’ Geōgraphikḕ Hyphḗgēsis by Jacopo d’Angelo (c. 1360 – 1411) in 1406. A reliable and accurate astronomy was needed to determine longitude and latitude. Other driving forces behind the need for renewal and reform were astrology, principally in the form of astro-medicine, a widened interest in surveying driven by changes in land ownership and navigation as the Europeans began to widen and expand their trading routes and to explore the world outside of Europe.

2880px-1660_celestial_map_illustrating_Claudius_Ptolemy's_model_of_the_Universe

The Ptolemaic Cosmos: Andreas Cellarius, Harmonia Macrocosmica 1660 Source: Wikimedia Commons

At the beginning of the fifteenth century the predominant system was an uneasy marriage of Aristotelian cosmology and Ptolemaic astronomy, uneasy because they contradicted each other to a large extent. Given the need for renewal and reform there were lively debates about almost all aspects of the cosmology and astronomy throughout the fifteenth and sixteenth centuries, many aspects of the discussions had their roots deep in the European and Islamic Middle Ages, which shows that the 1400 years of unchallenged Ptolemaic geocentricity is a myth, although an underlying general acceptance of geocentricity was the norm.

A major influence on this programme of renewal was the invention of moving type book printing in the middle of the fifteenth century, which made important texts in accurate editions more readily available to interested scholars. The programme for renewal also drove a change in the teaching of mathematics and astronomy on the fifteenth century European universities. 

One debate that was new was on the nature and status of comets, a debate that starts with Toscanelli in the early fifteenth century, was taken up by Peuerbach and Regiomontanus in the middle of the century, was revived in the early sixteenth century in a Europe wide debate between Apian, Schöner, Fine, Cardano, Fracastoro and Copernicus, leading to the decisive claims in the 1570s by Tycho Brahe, Michael Mästlin, and Thaddaeus Hagecius ab Hayek that comets were celestial object above the Moon’s orbit and thus Aristotle’s claim that they were a sub-lunar meteorological phenomenon was false. Supralunar comets also demolished the Aristotelian celestial, crystalline spheres. These claims were acknowledged and accepted by the leading European Ptolemaic astronomer, Christoph Clavius, as were the claims that the 1572 nova was supralunar. Both occurrences shredded the Aristotelian cosmological concept that the heaven were immutable and unchanging.

The comet debate continued with significant impact in 1618, the 1660s, the 1680s and especially in the combined efforts of Isaac Newton and Edmund Halley, reaching a culmination in the latter’s correct prediction that the comet of 1682 would return in 1758. A major confirmation of the law of gravity.

During those early debates it was not just single objects, such as comets, that were discussed but whole astronomical systems were touted as alternatives to the Ptolemaic model. There was an active revival of the Eudoxian-Aristotelian homocentric astronomy, already proposed in the Middle Ages, because the Ptolemaic system, of deferents, epicycles and equant points, was seen to violate the so-called Platonic axioms of circular orbits and uniform circular motion. Another much discussed proposal was the possibility of diurnal rotation, a discussion that had its roots in antiquity. Also, on the table as a possibility was the Capellan system with Mercury and Venus orbiting the Sun in a geocentric system rather than the Earth.

2880px-Andreas_Cellarius_-_Planisphaerium_Copernicanum_Sive_Systema_Universi_Totius_Creati_Ex_Hypothesi_Copernicana_In_Plano_Exhibitum

The Copernican Cosmos: Andreas Cellarius, Harmonia Macrocosmica 1660 Source: Wikimedia Commons

Early in the sixteenth century, Copernicus entered these debates, as one who questioned the Ptolemaic system because of its breaches of the Platonic axioms, in particular the equant point, which he wished to ban. Quite how he arrived at his radical solution, replace geocentricity with heliocentricity we don’t know but it certainly stirred up those debates, without actually dominating them. The reception of Copernicus’ heliocentric hypothesis was complex. Some simply rejected it, as he offered no real proof for it. A small number had embraced and accepted it by the turn of the century. A larger number treated it as an instrumentalist theory and hoped that his models would deliver more accurate planetary tables and ephemerides, which they duly created. Their hopes were dashed, as the Copernican tables, based on the same ancient and corrupt data, proved just as inaccurate as the already existing Ptolemaic ones. Of interests is the fact that it generated a serious competitor, as various astronomers produced geo-heliocentric systems, extensions of the Capellan model, in which the planets orbit the Sun, which together with the Moon orbits the Earth. Such so-called Tychonic or semi-Tychonic systems, named after their most well-known propagator, incorporated all the acknowledged advantages of the Copernican model, without the problem of a moving Earth, although some of the proposed models did have diurnal rotation.

2880px-1660_chart_illustrating_Danish_astronomer_Tycho_Brahe's_model_of_the_universe

The Tychonic Cosmos: Andreas Cellarius, Harmonia Macrocosmica 1660 Source: Wikimedia Commons

The problem of inaccurate planetary tables and ephemerides was already well known in the Middle Ages and regarded as a major problem. The production of such tables was seen as the primary function of astronomy since antiquity and they were essential to all the applied areas mentioned earlier that were the driving forces behind the need for renewal and reform. Already in the fifteenth century, Regiomontanus had set out an ambitious programme of astronomical observation to provide a new data base for such tables. Unfortunately, he died before he even really got started. In the second half of the sixteenth century both Wilhelm IV Landgrave of Hessen-Kassel and Tycho Brahe took up the challenge and set up ambitious observation programmes that would eventually deliver the desired new, more accurate astronomical data.

At the end of the first decade of the seventeenth century, Kepler’s Astronomia Nova, with his first two planetary laws (derived from Tycho’s new accurate data), and the invention of the telescope and Galileo’s Sidereus Nuncius with his telescopic discoveries are, in the standard mythology, presented as significant game changing events in favour of heliocentricity. They were indeed significant but did not have the impact on the system debate that is usually attributed them. Kepler’s initial publication fell largely on deaf ears and only later became relevant. On Galileo’s telescopic observations, firstly he was only one of a group of astronomers, who in the period 1610 to 1613 each independently made those discoveries, (Thomas Harriot and William Lower, Simon Marius, Johannes Fabricius, Odo van Maelcote and Giovanni Paolo Lembo, and Christoph Scheiner) but what did they show or prove? The lunar features were another nail in the coffin of the Aristotelian concept of celestial perfection, as were the sunspots. The moons of Jupiter disproved the homocentric hypothesis. Most significant discovery was the of the phases of Venus, which showed that a pure geocentric model was impossible, but they were conform with various geo-heliocentric models.

1613 did not show any clarity on the way to finding the true model of the cosmos but rather saw a plethora of models competing for attention. There were still convinced supporters of a Ptolemaic model, both with and without diurnal rotation, despite the phases of Venus. Various Tychonic and semi-Tychonic models, once again both with and without diurnal rotation. Copernicus’ heliocentric model with its Ptolemaic deferents and epicycles and lastly Kepler’s heliocentric system with its elliptical orbits, which was regarded as a competitor to Copernicus’ system. Over the next twenty years the fog cleared substantially and following Kepler’s publication of his third law, his Epitome Astronomiae Copernicanae, which despite its title is a textbook on his elliptical system and the Rudolphine Tables, again based on Tycho’s data, which delivered the much desired accurate tables for the astrologers, navigators, surveyors and cartographers, and also of Longomontanus’ Astronomia Danica (1622) with his own tables derived from Tycho’s data presenting an updated Tychonic system with diurnal rotation, there were only two systems left in contention.

Around 1630, we now have two major world systems but not the already refuted geocentric system of Ptolemaeus and the largely forgotten Copernican system as presented in Galileo’s Dialogo but Kepler’s elliptical heliocentricity and a Tychonic system, usually with diurnal rotation. It is interesting that diurnal rotation became accepted well before full heliocentricity, although there was no actually empirical evidence for it. In terms of acceptance the Tychonic system had its nose well ahead of Kepler because of the lack of any empirical evidence for movement of the Earth.

Although there was still not a general acceptance of the heliocentric hypothesis during the seventeenth century the widespread discussion of it in continued in the published astronomical literature, which helped to spread knowledge of it and to some extent popularise it. This discussion also spread into and even dominated the newly emerging field of proto-sciencefiction.

Galileo’s Dialogo was hopelessly outdated and contributed little to nothing to the real debate on the astronomical system. However, his Discorsi made a very significant and important contribution to a closely related topic that of the evolution of modern physics. The mainstream medieval Aristotelian-Ptolemaic cosmological- astronomical model came as a complete package together with Aristotle’s theories of celestial and terrestrial motion. His cosmological model also contained a sort of friction drive rotating the spheres from the outer celestial sphere, driven by the unmoved mover (for Christians their God), down to the lunar sphere. With the gradual demolition of Aristotelian cosmology, a new physics must be developed to replace the Aristotelian theories.

Once again challenges to the Aristotelian physics had already begun in the Middle Ages, in the sixth century CE with the work of John Philoponus and the impetus theory, was extended by Islamic astronomers and then European ones in the High Middle Ages. In the fourteenth century the so-called Oxford Calculatores derived the mean speed theorem, the core of the laws of fall and this work was developed and disseminated by the so-called Paris Physicists. In the sixteenth century various mathematicians, most notably Tartaglia and Benedetti developed the theories of motion and fall further. As did in the early seventeenth century the work of Simon Stevin and Isaac Beeckman. These developments reached a temporary high point in Galileo’s Discorsi. Not only was a new terrestrial physics necessary but also importantly for astronomy a new celestial physics had to be developed. The first person to attempt this was Kepler, who replaced the early concept of animation for the planets with the concept of a force, hypothesising some sort of magnetic force emanating from the Sun driving the planets around their orbits. Giovanni Alfonso Borelli also proposed a system of forces as the source of planetary motion.

Throughout the seventeenth century various natural philosophers worked on and made contributions to defining and clarifying the basic terms that make up the science of dynamics: force, speed, velocity, acceleration, etc. as well as developing other areas of physics, Amongst them were Simon Stevin, Isaac Beeckman, Borelli, Descartes, Pascal, Riccioli and Christiaan Huygens. Their efforts were brought together and synthesised by Isaac Newton in his Principia with its three laws of motion, the law of gravity and Kepler’s three laws of planetary motion, which laid the foundations of modern physics.

In astronomy telescopic observations continued to add new details to the knowledge of the solar system. It was discovered that the planets have diurnal rotation, and the periods of their diurnal rotations were determined. This was a strong indication the Earth would also have diurnal rotation. Huygens figured out the rings of Saturn and discovered Titan its largest moon. Cassini discovered four further moons of Saturn. It was already known that the four moons of Jupiter obeyed Kepler’s third law and it would later be determined that the then known five moons of Saturn also did so. Strong confirming evidence for a Keplerian model.

Cassini showed by use of a heliometer that either the orbit of the Sun around the Earth or the Earth around the Sun was definitively an ellipse but could not determine which orbited which. There was still no real empirical evidence to distinguish between Kepler’s elliptical heliocentric model and a Tychonic geo-heliocentric one, but a new proof of Kepler’s disputed second law and an Occam’s razor argument led to the general acceptance of the Keplerian model around 1660-1670, although there was still no empirical evidence for either the Earth’s orbit around the Sun or for diurnal rotation. Newton’s Principia, with its inverse square law of gravity provided the physical mechanism for what should now best be called the Keplerian-Newtonian heliocentric cosmos.

Even at this juncture with a very widespread general acceptance of this Keplerian-Newtonian heliocentric cosmos there were still a number of open questions that needed to be answered. There were challenges to Newton’s work, which, for example, couldn’t at that point fully explain the erratic orbit of the Moon around the Earth. This problem had been solved by the middle of the eighteenth century. The mechanical philosophers on the European continent were anything but happy with Newton’s gravity, an attractive force that operates at a distance. What exactly is it and how does it function? Questions that even Newton couldn’t really answer. Leibniz also questioned Newton’s insistence that time and space were absolute, that there exists a nil point in the system from which all measurement of these parameters are taken. Leibniz preferred a relative model.

There was of course also the very major problem of the lack of any form of empirical evidence for the Earth’s movement. Going back to Copernicus nobody had in the intervening one hundred and fifty years succeeded in detecting a stellar parallax that would confirm that the Earth does indeed orbit the Sun. This proof was finally delivered in 1725 by Samuel Molyneux and James Bradley, who first observed, not stellar parallax but stellar aberration. An indirect proof of diurnal rotation was provided in the middle of the eighteenth century, when the natural philosophers of the French Scientific Academy correctly determined the shape of the Earth, as an oblate spheroid, flattened at the pols and with an equatorial bulge, confirming the hypothetical model proposed by Newton and Huygens based on the assumption of a rotating Earth.

Another outstanding problem that had existed since antiquity was determining the dimensions of the known cosmos. The first obvious method to fulfil this task was the use of parallax, but whilst it was already possible in antiquity to determine the distance of the Moon reasonably accurately using parallax, down to the eighteenth century it proved totally impossible to detect the parallax of any other celestial body and thus its distance from the Earth. Ptolemaeus’ geocentric model had dimensions cobbled together from its data on the crystalline spheres. One of the advantages of the heliocentric model is that it gives automatically relative distances for the planets from the sun and each other. This means that one only needs to determine a single actually distance correctly and all the others are automatically given. Efforts concentrated on determining the distance between the Earth and the Sun, the astronomical unit, without any real success; most efforts producing figures that were much too small.

Developing a suggestion of James Gregory, Edmond Halley explained how a transit of Venus could be used to determine solar parallax and thus the true size of the astronomical unit. In the 1760s two transits of Venus gave the world the opportunity to put Halley’s theory into practice and whilst various problems reduced the accuracy of the measurements, a reasonable approximation for the Sun’s distance from the Earth was obtained for the very first time and with it the actually dimensions of the planetary part of the then known solar system. What still remained completely in the dark was the distance of the stars from the Earth. In the 1830s, three astronomers–Thomas Henderson, Friedrich Wilhelm Bessel and Friedrich Georg Wilhelm von Struve–all independently succeeded in detecting and measuring a stellar parallax thus completing the search for the dimensions of the known cosmos and supplying a second confirmation, after stellar aberration, for the Earth’s orbiting the Sun.

In 1851, Léon Foucault, exploiting the Coriolis effect first hypothesised by Riccioli in the seventeenth century, finally gave a direct empirical demonstration of diurnal rotation using a simple pendulum, three centuries after Copernicus published his heliocentric hypothesis. Ironically this demonstration was within the grasp of Galileo, who experiment with pendulums and who so desperately wanted to be the man who proved the reality of the heliocentric model, but he never realised the possibility. His last student, Vincenzo Viviani, actually recorded the Coriolis effect on a pendulum but didn’t realise what it was and dismissed it as an experimental error.

From the middle of the eighteenth century, at the latest, the Keplerian-Newtonian heliocentric model had become accepted as the real description of the known cosmos. Newton was thought not just to have produced a real description of the cosmos but the have uncovered the final scientific truth. This was confirmed on several occasions. Firstly, Herschel’s freshly discovered new planet Uranus in 1781 fitted Newton’s theories without problem, as did the series of asteroids discovered in the early nineteenth century. Even more spectacular was the discovery of Neptune in 1846 based on observed perturbations from the path of Uranus calculated with Newton’s theory, a clear confirmation of the theory of gravity. Philosophers, such as Immanuel Kant, no longer questioned whether Newton had discovered the true picture of the cosmos but how it had been possible for him to do so.

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However, appearances were deceptive, and cracks were perceptible in the Keplerian-Newtonian heliocentric model. Firstly, Leibniz’s criticism of Newton’s insistence on absolute time and space rather than a relative model would turn out to have been very perceptive. Secondly, Newton’s theory of gravity couldn’t account for the observed perihelion precession of the planet Mercury. Thirdly in the 1860s, based on the experimental work of Michael Faraday, James Maxwell produced a theory of electromagnetism, which was not compatible with Newtonian physics. Throughout the rest of the century various scientists including Hendrik Lorentz, Georg Fitzgerald, Oliver Heaviside, Henri Poincaré, Albert Michelson and Edward Morley tried to find a resolution to the disparities between the Newton’s and Maxwell’s theories. Their efforts finally lead to Albert Einstein’s Special Theory of Relativity and then on to his General theory of Relativity, which could explain the perihelion precession of the planet Mercury. The completion of the one model, the Keplerian-Newtonian heliocentric one marked the beginnings of the route to a new system that would come to replace it.

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Christmas Trilogy 2020 Part 3: The peregrinations of Johannes K

We know that human beings have been traversing vast distances on the surface of the globe since Homo sapiens first emerged from Africa. However, in medieval Europe it would not have been uncommon for somebody born into a poor family never in their life to have journeyed more than perhaps thirty kilometres from their place of birth. Maybe a journey into the next larger settlement on market day or perhaps once a year to an even larger town for a fair on a public holiday. This might well have been Johannes Kepler’s fate, born as he was into an impoverished family, had it not been for his extraordinary intellectual abilities. Although he never left the Southern German speaking area of Europe (today, Southern Germany, Austria and the Czech Republic), he managed to clock up a large number of journey kilometres over the fifty-eight years of his life. In those days there was, of course, no public transport and in general we don’t know how he travelled. We can assume that for some of his longer journeys that he joined trader caravans. Traders often travelled in large wagon trains with hired guards to protect them from thieves and marauding bands and travellers could, for a fee, join them for protection. We do know that as an adult Kepler travelled on horseback but was often forced to go by foot due to the pain caused by his piles.[1]

It is estimated that in the Middle ages someone travelling on foot with luggage would probably only manage 15 km per day going up to perhaps 22 km with minimal luggage. A horse rider without a spare mount maybe as much as 40 km per day, with a second horse up to 60 km per day. I leave it to the reader to work out how long each of Kepler’s journeys might have taken him.

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Johannes Kepler Source: Wikimedia Commons

Johannes’ first journey from home took place, when he attended the convent-school in Adelberg at the age of thirteen, which lies about 70 km due west of his birthplace, Weil der Stadt, and about 90 km, also due west of Ellmendigen, where his family were living at the time.

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Adelberg Convent Source: Wikimedia Commons

His next journey took place a couple of years later when he transferred to the Cistercian monastery in Maulbronn about 50 km north of Weil der Stadt and 30 west of Ellmendingen.

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Maulbronn Monastery Source: Wikimedia Commons

Finished with the lower schools in 1589, he undertook the journey to the University of Tübingen, where he was enrolled in the Tübinger Stift, about 40 km south of Weil der Stadt.

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The Evangelical Tübinger Stift on the banks of the Neckar Source: WIkimedia Commons

Johannes’ first really long journey took place in 1594, when on 11 April he set out for Graz the capital city of Styria in Austria to take up the posts of mathematics teacher in the Lutheran academy, as well as district mathematicus, a distance of about 650 km. The young scholar would have been on the road for quite a few days.

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Graz, Mur und Schloßberg, Georg Matthäus Vischer (1670) Source: Wikimedia Commons

Although he only spent a few years in Graz, Kepler manged at first to stabilise his life even marrying, Barbara Müller, and starting a family. However, the religious conflicts of the period intervened and Kepler, a Lutheran Protestant living in a heavily Catholic area became a victim of those conflicts. First, the Protestants of the area were forced to convert or leave, which led to the closing of the school where Kepler was teaching and his losing his job. Because of his success as astrologer, part of his duties as district mathematicus, Kepler was granted an exception to the anti-Protestant order, but it was obvious that he would have to leave. He appealed to Tübingen to give him employment, but his request fell on deaf ears. The most promising alternative seemed to be to go and work for Tycho Brahe, the Imperial Mathematicus, currently ensconced in the imperial capital, Prague, a mere 450 km distant.

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Prague in the Nuremberg Chronicle 1493 Source: Wikimedia Commons

At first Kepler didn’t know how he would manage the journey to Prague to negotiate about possible employment with Tycho. However, an aristocratic friend was undertaking the journey and took Johannes along as a favour. After, several weeks of fraught and at times downright nasty negotiations with the imperious Dane, Kepler was finally offered employment and with this promise in his pocket he returned to Graz to settle his affairs, pack up his household and move his family to Prague. He made the journey between Graz and Prague three times in less than a year.

Not long after his arrival in Prague, with his family, Tycho died and Kepler was appointed his successor, as Imperial Mathematicus, the start of a ten year relatively stable period in his life. That is, if you can call being an imperial servant at the court of Rudolf II, stable. Being on call 24/7 to answer the emperor’s astrological queries, battling permanently with the imperial treasury to get your promised salary paid, fighting with Tycho’s heirs over the rights to his data. Kepler’s life in Prague was not exactly stress free.

1608 saw Johannes back on the road. First to Heidelberg to see his first major and possibly most important contribution to modern astronomy, his Astronomia Nova (1609), through the press and then onto the book fair in Frankfurt to sell the finished work, that had cost him several years of his life. Finally, back home to Prague from Frankfurt. A total round-trip of 1100 km, plus he almost certainly took a detour to visit his mother somewhere along his route.

Back in Prague things began to look rather dodgy again for Kepler and his family, as Rudolf became more and more unstable and Johannes began to look for a new appointment and a new place to live. His appeals to Tübingen for a professorship, not an unreasonable request, as he was by now widely acknowledged as Europe’s leading theoretical astronomer, once again fell on deaf ears. His search for new employment eventually led him to Linz the capital city of Upper Austria and the post of district mathematicus. 1612, found Johannes and his children once again on the move, his wife, Barbara, had died shortly before, this time transferring their household over the comparatively short distance of 250 km.

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Linz anno 1594 Source: Wikimedia Commons

Settled in Linz, Kepler married his second wife, Susanna Reuttinger, after having weighed up the odds on various potential marriage candidates and the beginning of a comparative settled fourteen-year period in his life. That is, if you can call becoming embroiled in the Thirty Years War and having your mother arrested and charged with witchcraft settled. His mother’s witchcraft trial saw Johannes undertaking the journey from Linz to Tübingen and home again, to organise and conduct her defence, from October to December in 1617 and again from September 1620 to November 1621, a round trip each time of about 1,000 km, not to forget the detours to Leonberg, his mother’s home, 50 km from Tübingen, from where he took his mother, a feeble woman of 70, back to Linz on the first journey.

In 1624, Johannes set out once again, this time to Vienna, now the imperial capital, to try and obtain the money necessary to print the Rudolphine Tables from Ferdinand II the ruling emperor, just 200 km in one direction. Ferdinand refused to give Kepler the money he required, although the production of the Rudolphine Tables had been an imperial assignment. Instead, he ordered the imperial treasury to issues Kepler promissory notes on debts owed to the emperor by the imperial cities of Kempten, Augsburg and Nürnberg, instructing him to go and collect on the debts himself. Kepler returned to Linz more than somewhat disgruntled and it is not an exaggeration that his life went downhill from here.

Kepler set out from Linz to Augsburg, approximately 300 km, but the Augsburg city council wasn’t playing ball and he left empty handed for Kempten, a relatively short 100 km. In Kempten the authorities agreed to purchase and pay for the paper that he needed to print the Rudolphine Tables. From Kempten he travelled on to Nürnberg, another 250 km, which he left again empty handed, returning the 300 km to Linz, completing a nearly 1,000 km frustrating round trip that took four months.

In 1626, the War forced him once again to pack up his home and to leave Linz forever with his family. He first travelled to Regensburg where he found accommodation for his family before travelling on to Ulm where he had had the paper from Kempten delivered so that he could begin printing, a combined journey of about 500 km. When the printing was completed in 1627, having paid the majority of the printing costs out of his own pocket, Kepler took the entire print run to the bookfair in Frankfurt and sold it in balk to a book dealer to recoup his money, another journey of 300 km. He first travelled back to Ulm and then home to his family in Regensburg, adding another 550 km to his life’s total. Regensburg was visited by the emperor and Wallenstein, commander in chief of the Catholic forces, and Kepler presented the Tables to the Emperor, who received them with much praise for the author.

In 1628, he entered the service of Wallenstein, as his astrologer, moving from Regensburg to Wallenstein’s estates in the Dutchy of Sagan, yet another 500 km. In 1630, the emperor called a Reichstag in Regensburg and on 8 October Kepler set out on the last journey of his life to attend. Why he chose to attend is not very clear, but he did. He journeyed from Zagan to Leipzig and from there to Nürnberg before going on to Regensburg a total of 700 km. He fell ill on his arrival in Regensburg and died 15 November 1630.

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Regensburg Nuremberg Chronicle 1493 Source: Wikimedia Commons

The mathematical abilities of the young boy born to an impoverish family in Weil der Stadt fifty-eight-years earlier had taken him on a long intellectual journey but also as we have seen on a long physical one, down many a road.

 

[1] I almost certainly haven’t included all of the journeys that Kepler made in his lifetime, but I think I’ve got most of the important ones. The distances are rounded up or down and are based on the modern distances by road connecting the places travelled to and from. The roads might have run differently in Kepler’s day.

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The solar year ends and starts with a great conjunction

Today is the winter solstice, which as I have explained on various occasions, in the past, is for me the natural New Year’s Eve/New Year’s Day rather than the arbitrary 31 December/1 January.

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Obligatory Stonehenge winter solstice image

Today in also the occurrence of a so-called great conjunction in astronomy/astrology, which is when, viewed from the Earth, Jupiter and Saturn appear closest together in the night sky. Great conjunctions occur every twenty years but this one is one in which the two planets appear particularly close to each other.

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Great conjunctions played a decisive role in the life of Johannes Kepler. As a youth Kepler received a state grant to study at the University of Tübingen. The course was a general-studies one to prepare the students to become Lutheran schoolteachers or village pastors in the newly converted Protestant state. Kepler, who was deeply religious, hoped to get an appointment as a pastor but when a vacancy came up for Protestant mathematics teacher in Graz, Michael Mästlin recommended Kepler and so his dream of becoming a pastor collapsed. He could have turned down the appointment but then he would have had to pay back his grant, which he was in no position to do so.

In 1594, Kepler thus began to teach the Protestant youths of Graz mathematics. He accepted his fate reluctantly, as he still yearned for the chance to serve his God as a pastor. Always interested in astronomy and converted to heliocentricity by Michael Mästlin, whilst still a student, he had long pondered the question as to why there were exactly six planets. Kepler’s God didn’t do anything by chance, so there had to be a rational reason for this. According to his own account, one day in class whilst explaining the cyclical nature of the great conjunctions in astronomy/astrology, which is when, viewed from the Earth, Jupiter and Saturn appear closest together in the night sky, he had a revelation.  Looking at the diagram that he had drawn on the board he asked himself, “What if his God’s cosmos was a geometrical construction and this was the determining factor in the number of planets?”

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Kepler’s geometrical diagram of the cyclical nature of the great conjunctions in his Mysterium Cosmographicum Source: Linda Hall Library

Kepler determined from that point on in his life to serve his God as an astronomer by revealing the geometric structure of God’s cosmos. He first experimented with various regular polygons, inspired by the great conjunction diagram, but couldn’t find anything that fit, so he moved into three dimensions and polyhedra. Here he struck gold and decided that there were exactly six planets because their orbital spheres were separated by the five regular Platonic solids.

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Source: Wikimedia Commons

 

He published this theory in his first academic book, Mysterium Cosmographicum (lit. The Cosmographic Mystery, alternately translated as Cosmic MysteryThe Secret of the World) 1597. The book also contains his account of the revelation inspired by the great conjunction diagram. This was the start of his whole life’s work as a theoretical astronomer, which basically consisted of trying to fine tune this model.

In the early seventeenth century, Kepler was still deeply religious, a brilliant mathematician and theoretical astronomer, and a practicing astrologer. As an astrologer Kepler rejected the standard Ptolemaic sun sign i.e., Aquarius, Virgo, Gemini, etc., astrology. Normal horoscope astrology. Sun signs, or as most people call them star signs, are 30° segments of the circular ecliptic, the apparent path of the Sun around the Earth and not the asterisms or stellar constellations with the same names. Kepler developed his own astrology based entirely on planetary aspects, that is the angles subtended by the planets with each other on the ecliptic. (see the Wikipedia article Astrological aspect). Of course, in Kepler’s own astrology conjunctions play a major role.

Turning to the so-called Star of Bethlehem, the men from the east (no number is mentioned), who according to Matthew 2:2, followed the star were, in the original Greek, Magoi (Latin/English Magi) and this means they were astrologers and not the sanitised wise men or kings of the modern story telling. Kepler would have been very well aware of this. This led Kepler to speculate that what the Magoi followed was an important astrological occurrence and not a star in the normal meaning of the word. One should note that in antiquity all visible celestial objects were stars. Stars simple Asteres, planets (asteres) planētai wandering (stars) and a comet (aster) komētēs, literally long-haired (star), so interpreting the Star of Bethlehem as an astrological occurrence was not a great sketch.

His revelation in 1603 was that this astrological occurrence was a great conjunction and in fact a very special one, a so-called fiery trigon, one that links the three fire signs, Aries, Leo, Sagittarius.

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Calculating backwards, Kepler the astronomer, determined that one such had occurred in 7 BCE and this was the star that the Magoi followed.

Whether Kepler’s theory was historically correct or an accepted view in antiquity is completely impossible to determine, is the Bible story of Jesus’ birth even true? In Kepler’s own time, nobody accepted his deviant astrology, so I very much doubt that many people accepted his Star of Bethlehem story, which he published in his De Stella Nova in Pede Serpentarii (On the New Star in the Foot of the Serpent Handler) in 1606.

I’m sure that a great conjunction on the date of the winter solstice has a very deep astrological significance but whether astrologers will look back and say, “Ah, that triggered this or that historical occurrence” only the future will tell.

I thank all of those who have read, digested and even commented upon my outpourings over the last twelve months and fully intend to do my best to keep you entertained over the next twelve. No matter which days you choose to celebrate during the next couple of weeks, in which way whatsoever and for what reasons, I wish all of my readers all the best and brace yourselves for another Renaissance Mathematicus Christmas Trilogy starting on 25 December.

 

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