Libration and earthshine

30.12.2025 - 11:30 pm

In the last few month I have published several images and videos of our Moon rendered with Povray, see section Astro-3D. There were some nice results, but always with room for improvement. At the moment I'm working on the simulation of libration and earthshine, which should make everything more realistic.

The libration is responsible for the "rolling" that causes the Moon to wobble around two axes during a lunar day. The earthshine provides a second, weak light source that illuminates the earth-facing side a little, if it is not illuminated by the sun.

I have implemented both into new videos as a test. The earthshine is set to a maximum of 2 percent of sunlight, realistically it would be well below 1 percent. For presentation purposes it could be a bit more, depending on the monitor settings there is not much to see of it so far. The libration is set at +/- 6 degrees in both directions.

Since I have already shown the front and back sides in videos, this time the western and eastern hemispheres were my test subjects, as if you were looking at the Moon from a location to the left or right of the Earth. These views have their own charm, as they show the differences between the dark, relatively flat front side and the jagged back side at a glance.

Two small animations as a farewell to 2025.

I wish everyone a happy new year.

Martin Seydler

View of the west side of the Moon, the Earth would be outside the image on the right.

20 seconds - 1920x1080 px - 11 MB
600 frames - 30 fps - 20 crf - lib264

View of the east side of the Moon, the Earth would be outside the image on the left.

20 seconds - 1920x1080 px - 11 MB
600 frames - 30 fps - 20 crf - lib264

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