- I hope someone can help with this one...I've tried to hunt these
calculations down on the web, but became so overwhelmed and confused
by so many similar formulae that I decided to ask the pros...
I'm designing an electronic device known as "Digital Setting Circles"
for an alt-az (altitude-azimuth)telescope, which moves horizontally
and vertically, as opposed to equatorially, and need to know how to
start from two known sets of "celestial" coordinates, say stars used
to initialize the system, convert them to alt-az, rotate them to my
horizon coordinates, add the movement of a set of encoders i mounted
to sense the motion of the telescope, de-rotate and convert back
to "celestial" coordinates again for display - all without having to
enter any location information (latitude, longitude) or sidereal time.
It seems that, as long as you have some "knowns", you can do these
conversions for alt-az movements, without having to know location or
hour angle, because you're only solving for the movement. In other
words, how many degress celestially do my encoders travel, given the
tilt of the earth. I hope that is clear.