|  |
| |
As with Section 4.4, “main()”, first we check out
the command line arguments, then convert from horizon to
celestial coordinates and print the result.
# - - - - - m a i n
def main():
"""Main program for aard.
"""
#-- 1 --
# [ if sys.argv contains a valid set of command line
# arguments ->
# altAz := the azimuth and altitude as
# a sidereal.AltAz instance
# latLon := the observer's location as a
# sidereal.LatLon instance
# dt := the observer's date and time as a
# datetime.datetime instance
# else ->
# sys.stderr +:= error message
# stop execution ]
altAz, latLon, dt = checkArgs()
#-- 2 --
# [ if dt has no time zone information ->
# utc := dt
# else ->
# utc := the UTC equivalent to dt ]
if ( (dt.tzinfo is None) or
(dt.utcoffset() is None) ):
utc = dt
else:
utc = dt - dt.utcoffset()
Display the local sidereal time in case the observer is interested.
#-- 3 --
# [ sys.stdout +:= local sidereal time for dt and latLon ]
gst = sidereal.SiderealTime.fromDatetime ( utc )
lst = gst.lst ( latLon.lon )
print "Horizon coordinates:", altAz
print "Observer's location:", latLon
print "Observer's time:", dt
print "Local sidereal time is", lst
Here is where this script diverges from Section 4.4, “main()”. To convert from horizon to
equatorial coordinates, you need a local sidereal time
and an observer's location.
#-- 4 --
# [ raDec := equatorial coordinates of self for local
# sidereal time (lst) and location (latLon) ]
raDec = altAz.raDec ( lst, latLon )
#-- 5 --
print "Equatorial coordinates:", raDec