# Moonlit sources and credits

Astronomical calculations use [Astronomy Engine](https://github.com/cosinekitty/astronomy), by Don Cross, under the MIT license. The full license is included in the app and source folder. The vendored source is pinned to commit `865d3da7d8112bbc7911238052c6af4aaf877181`.

Lunar surface imagery: NASA’s Scientific Visualization Studio, [CGI Moon Kit](https://svs.gsfc.nasa.gov/4720/), 2025 LROC color map (`lroc_color_2k.jpg`). Credit: NASA’s Scientific Visualization Studio; Ernie Wright (USRA); LRO/LROC instrument teams. The map is intended for visualization; it is not a scientific surface measurement product.

The learning content is an original summary, grounded in NASA’s [Moon Phases](https://science.nasa.gov/moon/moon-phases/), [Top Moon Questions](https://science.nasa.gov/moon/top-moon-questions/), [orbital periods](https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question32.html), and [Eclipses and the Moon’s Orbit](https://eclipse.gsfc.nasa.gov/SEhelp/moonorbit.html).

Phase predictions are checked against the U.S. Naval Observatory’s [2026 primary phase table](https://aa.usno.navy.mil/calculated/moon/phases?year=2026).