Since the relation between alt-az and RA-dec coordinates is time-dependent, if CdC were to send alt-az coordinates for pointing, it would have to know how fast your scope moves, so it could send the scope to where the object _will be_, at the time it gets there. That adds even more complexity, since the "time to get there" will depend on the distance to the target. RA-dec is the sky's natural coordinate system, so charting programs start with that.
I'm assuming your mount is alt-az, otherwise there's no reason to be concerned with alt-az coordinates at all. So in this case your mount controller will need to routinely do the coordinate transformation anyway. -John ----- Original Message ---- > From: ulrichkorth <[EMAIL PROTECTED]> > > Hi Chris, > next question from beginner: Is it true, that NOT CdC - or any other > PC-Astro-Program - will always calculate Altitude and Azimut but > this is task of the scope's controller itself. That was the > intention of my first question - as we build the scopes controller > ourselves we would like not to calculate here - but would like to > get these data from PC, which has more calculation power and more > accuracy. > Ulrich > > --- In [email protected], Chris Rowland > wrote: > > > > Ra and Dec are better for pointing to celestial objects because > they > > don't change as the Earth rotates. > > > > Look for ASCOM for a way to communicate with Ceil. > > > > Chris > > > > ulrichkorth wrote: > > > Hi sky friends, > > > we are beginners and want to use ciel. The communication to > teleskope > > > works well. But why does ciel only send RA and DEC and NOT also > ALT > > > and Azimut?? > > > As we are building the teleskope control and SW ourselves it > would be > > > easier to have ALT and Azimut from ciel. > > > > > > For some help and advice we would be very thankful. > > > > > > Kind regards > > > Ulrich and Michael Korth
