I am thinking about building a sector drive to track and photograph the night sky - long exposures. The unit will sit on a rotating level platform and align itself to N/S and set the latitude of the right ascension axis automatically. Leveling could also be automatic, but that's not essential.
The plan is to achieve North - South alignment and latitude setting by reference to an electronic compass (GPS?). The compass will operate on a level platform - no tilt issues. Latitude setting, derived from a GPS module, will be from 0 - 90 (North/South is irrelevant). The tracking drive will be static - that is, no electronic control, just relying on predetermined radii of the sector arm and drive pully/gear/friction drive.
I have looked at tilt sensors and accelerometers, GPS modules and compasses. I am a little confused about whether I should use a tilt sensor to measure the latitude setting of the unit - related to the GPS position, or an accelerometer. Furthermore, how accurate are electronic compasses - is a few arc seconds asking too much?
This will be my 5th Arduino project.