# Most of this code is ported from Fourmilab's javascript calendar converter
# http://www.fourmilab.ch/documents/calendar/
# which was developed by John Walker
#
# The algorithms are believed to be derived from the following source:
# Meeus, Jean. Astronomical Algorithms . Richmond: Willmann-Bell, 1991. ISBN 0-943396-35-2.
#    The essential reference for computational positional astronomy.
#
