The code can be found here: https://codeberg.org/x11cp/x11cp.git
git clone https://codeberg.org/x11cp/x11cp.git && cd x11cp/src/xmoontool
To compile this application, the following command should be used:
There is also a wrapper command in the top-level `Makefile` of the repository where this is can be run as:
The following libraries/dependencies are also required. The names of these will vary from each Linux distribution/BSD, hence the names of these libraries are generically specified:
NOTE: this application requires an 8-bit color depth display to run.
This will mean running this inside a Xephyr session
xmoontool is anapplication displaying real time information about the moon.
When it is iconified, it shows what the moon looks like in the sky (see screenshots).
This only works on 8-bit colour-depth displays due to how the XVisuals are used to render the pixmaps.
Interestingly, the following books were used as a mathematical aid for the program to calculate moon things:
Practical Astronomy With Your Calculatorby Peter Duffett-Smith, Second Edition, Cambridge University Press, 1981.
Astronomical Formulae for Calculatorsby Jean Meeus, Third Edition, Willmann-Bell, 1985.
Planetary Programs and Tables from -4000 to +2800by Pierre Bretagnon and Jean-Louis Simon, Willmann-Bell, 1986.
Celestial BASICby Eric Burgess, Revised Edition, Sybex, 1985.
Astronomy: From the Earth to the Universeby Jay M. Pasachoff, Second Edition, Saunders College Publishing, 1983
The red dot you can see on the iconified window is commemorative, showing Tranquility Base, to mark the 20th anniversary of Apollo 11 (at the time).