Files
astronomy/generate/libration
Don Cross a652da7b9e Rough version of Moon's rotation axis in C.
I used Cassini's Laws to derive an approximate solution
to the Moon's rotation axis. The error is on the order of
5 arcminutes. I still need to correct for physical libration.

I also need to find test data for the Moon's prime meridian
so that I can implement the spin angle calculation.
(I could use test data for all the planets' spins, for that matter.)
2021-12-05 13:22:00 -05:00
..

Acknowledgements

Moon libration data for the years 2020-2022 comes from NASA's Scientific Visualization Studio.

mooninfo_2020.txt comes from: Moon Phase and Libration 2020

mooninfo_2021.txt comes from: Moon Phase and Libration 2021

mooninfo_2022.txt comes from: Moon Phase and Libration 2022

These Moon Phase and Libration pages contain some wonderful videos, images, and explanatory text that help make the complexities of the Moon's orbit and libration understandable.

Further Reading

The PDF document Computation of the Quantities Describing the Lunar Librations in The Astronomical Almanac provides a detailed explanation of the meaning of lunar libration quantities like sub-solar angles, sub-earth angles, and polar position angles.