Astronomical Algorithms

This library implements algorithms from Jean Meeus, Astronomical Algorithms, 2nd English Edition, Willmann-Bell, Inc., Richmond, Virginia, 1999, with corrections as of June 15, 2005.

Gem astro-algo provides two modules:

• Astro which implements algorithms from the book. (require ‘astro-algo’)

• LunarYear which implements helper routines for calculating lunar years. (require ‘lunaryear’)

This gem also comes with several command line scripts.

equinox

prints the date and time of the vernal equinox for the given year.

lunarcalendar

prints a conversion chart between the customary Gregarian calendar and a lunar year beginning with the full moon on or before the vernal equinox.

moon_clock.rb

a Tk GUI application which displays information about the current lunation.

moons

prints the phases of the moon for the given year.

This is a work in progress. Only the algorithms from Astronomical Algorithms needed to support my hobby in the LunarYear have been implemented. I will add more algorithms from the book in time.