Greenwich Hour Angle

[pkay]

I am trying to write a program for my programmable calculator to calculate elevation / azimuth of an object (for my location and time) given Right Ascension and Declination.

I have a formula that requires the Greenwich Hour Angle of the Equinox at Jan 1, 2007 and I cannot seem to work out how to obtain it. Any clues?

If not does anyone have another formula?

Thanks in advance.

Regards
Peter

[a1call]

You can have Equinox times UTC /Greenwich here:

http://en.wikipedia.org/wiki/Equinox

You will need that value or something equivalent for the formula to work.

[tdvance]

This US Naval Observatory page on alt-az computations might help:

http://aa.usno.navy.mil/faq/docs/Alt_Az.php

[Tobin Dax]

This US Naval Observatory page on alt-az computations might help:

http://aa.usno.navy.mil/faq/docs/Alt_Az.php

That looks pretty good. A *lot* better than the astronomical almanac. That thing's darn near impossible to read.