Friday, February 18, 2011

Moon maps

Yesterday we had a precious evening with clear skies and a beautiful (almost) full moon. I tried to photograph it but I couldn't figure out the right settings (zoom, aperture, shutter speed) to take pictures through my binoculars. My best result is much worse than what I could do with my previous pocket camera. So I hope to get better pictures in the future.

Because I could not take the easy route I was forced to take the classic route - by drawing what I saw through the binoculars. My cheap Minolta 10x50 is much better than any telescope Galileo ever had. But my eyes are probably worse and my drawing skills are abominable.

It is not easy. The bright moon is blindingly bright through binoculars. The eyes need time to adapt to the darkness so you can see the page and the pencil lines in the darkness. And drawing to scale - the first time in my life - is frustrating. But the results are encouraging. Using a moon map I can recognize most landmarks that I drew.

The minimum size that I can draw reliably seems is 110 km for Gassendi crater. I don't trust myself in naming Manilius crater correctly, that one is 39 km in diameter. From the lunar mare I missed Nubium, Procellarum and Vaporum. Now compare this with Galileo Galilei. His moon map looks like this:

Much better draughtsmanship - I guess anyone could draw better in these times before photography - and more detail.

But even this pales in comparison with the drawings that I found in a second hand book at the Rotterdam book market. The theories in this book are interesting, but are completely discredited by modern science - there are no volcanoes, no atmosphere, (almost) no water and no lifeforms on the moon. But the drawings are superb and I wonder how the author did it.

Plate IV    Lunar mountains drawn by the author direct from telescopic observation, Above: the lunar Altai, Below: the Leibnitz mountains near the South pole of the Moon, seen on the morning terminator at the gibbous phase, northern libration projecting the peaks on to the skyline. (Drawn 31 may, 1955, 20h. 10m. to 20h. 25m. G.M.T., from observation with a 6 1/2- inch reflector, powers x240 and x360).

V. A. Firsoff, Strange world of the moon, an enquiry into lunar physics, Published 1959 by Hutchinson in London
Interactive moon map
A wonderful article about Galileo's moon drawings
A very interesting article about early lunar maps - Galileo's was not the first map
Another article about early moon maps

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