If you have ever looked at a map of the moon you might have noticed that many of the selenographical features are named after astronomers and you might just have asked yourself how come? At this point several of my readers are probably thinking what in the name of all that is holy is selenographical. Don’t worry my spell checker just asked the same question. Now geography is a Greek word that literally means earth-writing from geo meaning earth and graphos meaning writing. Selenography is moon-writing from Selene the Greek goddess of the moon and graphos. So selenographical features are what someone who is not a
pendent pedant like me would probably refer to incorrectly as geographical features of the moon. Now back to the main plot. The person who chose to name the selenographical feature after astronomers was the Jesuit mathematician, astronomer and physicist Giovanni Battista Riccioli who was born 17th April 1598.
Selenography was first made possible by the invention of the telescope in Middelburg in Holland in 1608. In fact the oldest extant record of an astronomer using a telescope as an astronomical instrument is a drawing of the moon made by Thomas Harriot on 26th July 1609.
Harriot’s drawings are very primitive, mere sketches, and cannot be compared with the justifiably famous moon drawings published by Galileo Galilei in his Sidereus Nuncius from 1610. Galileo unlike Harriot was a trained artist and realised that what he was seeing through his telescope were three dimensional landscape features, mountains, valleys, etc.
From then on selenography, mapping the moon, became a major occupation of telescopic astronomers. The three most extensive and accurate maps of the moon produced in the 17th century are those of Michel Florent van Langren from 1645, of Hevelius published in his
Selenpgraphia Selenographia 1647 and that of Grimaldi and Riccioli in the latter’s Almagestum Novum from 1651.
Michel Florent van Langrens map gives the major lunar features the names of Catholic royalty and saints. The maria were given Latin names of seas and oceans. Minor craters were given the names of astronomers, mathematicians, and other notable scholars of the past and present periods.
Hevelius ignored van Langrens nomenclature and named the lunar features after similar features on the earth using classical Greek and Latin names.
Riccioli and Grimaldi introduced a systematic nomenclature first dividing the moon into eight zones. Seas and the plains in between were given descriptive historical names, tranquillity, serenity etc. and they followed van Langren in naming the craters after scholars and in particular astronomers. As a gesture to the Catholic Church some craters were named after saints but only saints connected with astronomy. The Riccioli/Grimaldi nomenclature was the one that
one won the day and is still largely intact today.