[renormalised (Carl)]

Originally Posted by garymck

You'll be guiding on a star that doesn't rotate, while the field of the imaging camera does rotate, won't work. You need both camera and guide scope to rotate for imaging......

check out:

http://www.mapug-astronomy.net/astro...G/Derotatr.htm

cheers
Gary

That's why you can't use a guidescope with a derotator, only an OAG. Unless you're using it as a field rotator....basically a convenient way of changing the FoV perspective.