It’s the wrong telescope.

I know I announced a blogging hiatus yesterday, but I have some time evenings and I simply couldn’t ignore this.

Caroline Herschel
Source: Wikimedia Commons

 

Today is Caroline Herschel’s birthday and Google have celebrated it with a doodle, which is cool and an overdue acknowledgement of a great lady astronomer. If you don’t already know who Caroline Herschel is then you should read the two Guardian articles by Stuart Clark and Becky Higgitt. Google’s doodle is all well and good but I have a complaint, it’s the wrong telescope.

The Google doodle for Caroline Herschel’s 266th birthday. Photograph: google

If you look at the picture Caroline is standing behind a mounted telescope and in the animated version of the doodle she bends down to look through the telescope as a comet flies passed overhead. This is to acknowledge the fact that she is most well known for the eight comets that she discovered. So what’s my problem? The telescope displayed in the doodle is a refractor that is a telescope with lenses at the front, the objective, and at the back, the eyepiece or ocular. The problem is that the Herschels, that is Caroline and her brother William, used reflectors; that is telescopes that have a mirror and not a lens as objective and then a lens or lenses as the eyepiece to observe the image created by the mirror. To be precise they used Newtonian reflectors that they built themselves. That they used Newtonians was rather unusual at the time because most other professional, or serious amateur like the Herschels, astronomers used Gregorian reflector telescopes, which are of a different design. The Gregorian is actually superior but the Newton is simpler to construct and this is almost certainly the reason that William stuck with Newtonians.

Replica of a Herschel Newtonian Reflector. Herschel Museum Bath
Source: Wikimedia Commons

Added: 17 March 2016

If you go to the article Caroline Lucretia Herschel – comet huntress (h/t Tony Angel)on the second page you can see sketches of the comet-sweeper Newtonian reflectors that William built for Caroline, which are not quite as elegant or impressive as the telescope pictured above but which served their purpose admirably.

The fact that the doodle shows a refractor and not a reflector is, viewed historically, not a trivial matter. In the eighteenth century the reflectors were capable of resolving much weaker light sources than the contemporary refractors and were thus superior for the type of deep space celestial mapping that William Herschel pioneered and which he taught to his younger sister. To show Caroline using a refractor and not a Herschel Newtonian reflector is a complete historical misrepresentation and totally misleading.

Now Google might argue that your average Google doodle viewer would probably not recognise a Herschel Newtonian reflector as a telescope and therefore they put a simple refractor in the picture as a generic telescope that people would recognise as such. All well and good but I can best explain my aversion by a simple analogy.

Lewis Hamilton is the current world Formula One racing champion. I want you to imagine the following. Next season Hamilton wins his fourth world championship and Google celebrate the occasion with one of their doodles, unlikely but you never know. So we get a cartoon of the well know figure of Lewis Hamilton in a Formula One racing car but he is not driving a Mercedes, the team for which he drives and has won two of his three titles up till now, but a Ferrari because that is the generic racing car that most people see in their minds eye when they think of racing cars. The Lewis Hamilton fans would probably launch a crusade against the Google head quarters in Mountain View and hang the offending doodler from a lamppost.

As far as I’m concerned in the history of science details matter a lot and the fact that the Herschels used Newtonian reflectors is not a triviality but an important factor in the astronomical achievements for which they are justifiably renowned. It should also be pointed out that this renown led to William becoming one of the commercially most successful telescope constructors in the eighteenth century because other astronomers wanted to own one of those telescopes, which had made the discoveries of William and Caroline possible.