NavList:

I am sorry if this has been covered before but I took a sun sight today 23/02/2016 at 12:06:50 and looked up the GHA and Dec on Henning Umland's long term almanac http://www.celnav.de/longterm.htm which gives GHA of the Sun as  360° 00' 00'' and Dec  10° 45' 39'' S.

When I worked through the sight my sextant altitude was out by a couple of degrees so I redid the calculation usy pyephem, the Python language Ephemeris library http://rhodesmill.org/pyephem/ .  Here is my code by the way (marsham is just the name of the location)

import ephem
marsham=ephem.Observer()
marsham.date='2016/02/23 12:06:50'
marsham.lat, marsham.lon = '53.3280922','-1.9948138'
marsham.pressure=987
marsham.temp=10
sun = ephem.Sun()
sun.compute(marsham)
print("Sun Altitude and Az %s %s" % (sun.alt, sun.az))
print("Dec %s" % (sun.dec))
print("RA %s" % (sun.ra))
deg= ephem.degrees
print("GHA %s" % deg(marsham.sidereal_time()-sun.g_ra).norm)
print("Sextant reading with art horiz %s" % deg(sun.alt*2))

And the output

Sun Altitude and Az 26:41:43.2 175:59:18.8
Dec -9:55:54.7
RA 22:24:43.19
GHA 356:21:40.5
Sextant reading with art horiz 53:23:26.3
bill@bill-XPS:~/astronav$ python pyephex.py
Sun Altitude and Az 26:41:43.2 175:59:18.8
Dec -9:55:54.7
RA 22:24:43.19
GHA 356:21:40.5
Sextant reading with art horiz 53:23:26.3

Which agrees with what I measured up to index error. Can anyone check the calculations with their own almanac software and see if they agree with me that PyEphem is right?

Thanks Bill