RA & Dec to Alt, Az

[rmcpb]

Does anyone know of the location of a formula to convert the RA and Dec of an object to the Alt/Az.

I know I can get this info from any number of programs but there must be a formula that can be applied to get the correct coordinates for an object in live time.

[ving]

cos Z = sin(lat) sin(dec) + cos(lat) cos(dec) cos(hr)

Z is the zenith distance and hr is the hour angle.

cos A = (sin(lat) cos (Z) - sin (dec)) / cos(lat) sin (Z)

A is the Azimuth.
http://astro.umsystem.edu/atm/ARCHIVES/SEP96/msg00355.html
http://astro.umsystem.edu/atm/ARCHIVES/SEP96/msg00357.html
:confused:

[ving]

http://idlastro.gsfc.nasa.gov/ftp/pro/astro/eq2hor.pro
:confuse3:

http://www.geocities.com/kellertuberg/telescope/software.html

[bojan]

Hi Rob, have a look at
http://astro.berkeley.edu/~heiles/handouts/ay120coord.pdf
There you will find the answer to your question :-)
Bojan

[ving]

a proggy i think:
http://home.att.net/~srschmitt/celestial2horizon.html

[rmcpb]

Thanks Bojan and Dave. Talk about quick service :)

[ving]

who was talking about quick servive? ;)

no problem rob :)