Last night I made a sketch of Lunar crater Gauss and its surroundings. While archiving the sketch this morning I realised I already sketched this part of the Moon almost a year ago, so I got the idea of a side by side comparison to show the effect of lunation. To my surprise I found out these sketches were made at the exact same lunation: 15.5 days. The difference in lighting therefore had to be caused mainly by the Moon’s libration; the slow wobbling of the Moon in its orbit. A pleasant suprise to find out I sketched this phenomenon totally unintentionally!
Both sketches were made using a 3″ Polarex Unitron refractor at 171x, with a white pastel pencil on black paper. Orientation and size were matched using Photoshop.
Object Name: Gauss
Object Type: Lunar crater, libration
Location: Deventer, The Netherlands
Date: December 8, 2014
Media: white pastel pencil, black paper