Improved Planet Program

Fred Mendenhall fred at inuxe.UUCP
Fri Jan 3 05:40:50 AEST 1986


I've just completed adding the outer planets to my program
and have posted it on net.sources as planet2.c. I've cleaned up
some bugs from the first version as well as making the input
pattern easier for people not living in North America. I have also
posted a copy of the following info file on net.sources.


Planet2.c is the c source for a program that determines the
Right Ascension and Declination for the Sun and the planets Mercury 
through Neptune as viewed from the center of the Earth given the time,
date and time zone correction for UT.

The results are for the epoch of the date, hence if the date is
Jan 1, 1985 the coordinates are for epoch 1985.0 and not
for the standard 1950 or 2000 dates of most star atlases.

Accuracy? No promises, but the results should be accurate to
.01 Degrees for Nep and Ura and to tens of arc seconds for the
rest of the planets. ( I've only checked the program against two dates
from a set of 1981 and 1983 Astronomy magazines) These results are 
not good enough to predict occultations but should be good enough to use 
for finding the planets using the setting circles on a telescope.

The effects of nutation, aberration and parallax are not considered.

This program runs on our VAX's 11/780's under UNIX system V.

				Clear Skies,

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