🚀 go-pugleaf

In article <spitz.720440629@irb.uni-hannover.de> spitz@irb.uni-hannover.de (Jan
Spitzkowsky) writes:
>Please help,
>
>I need an algorithm for calculating the lunar phases.
>I need it for computing the red letter days, most of them
>depend on the moon like Easter.

I'd really like to know what red letter days are. I've heard the phrase
but I've never known what it meant! Please let the rest of us know. The
computation of the date of Easter is done by numerological rather than
astronomical algorithm, and that may help answer your question.

See "Explanatory Supplement to the Astronomical Ephemeris and the American 
Ephemeris and Nautical Almanac" in your library, the chapter on Calendars.
You will learn that the algorithm has nothing to do with the physical moon
for most Christians. Orthodox Christians are the only ones who calculate 
the phase of the physical moon, and they reckon day of the week by the 
longitude of Jerusalem. I don't know whether they use apparent solar time 
or mean solar time.

Leigh