Hi Robert
Some CGEM's suffer from drive cogging in the servo motor. It
may be what's causing your spikes. However if the mount is ok with the other scope then your probably ok in that respect.
This link show's a great way to check if your dec motor is affected
http://www.youtube.com/watch?v=bVqW8ZGi7_4
The issue has also been discussed heavily in this thread.
http://www.cloudynights.com/ubbthrea.../o/all/fpart/1
Celestron are close the releasing a new MC firmware version which should fix the problem.
You could also try higher anti backlash settings in dec.
I'm very interested that your polar alignment procedure worked. Do you have the Nexstar + Hand control? The polar align feature hasn't worked for me from day one. Derik form celestron has recently confirmed that there is a bug in the Nexstar + HC when performing the ASPA in the southern hemisphere.
It hopefully be fixed when the dec issue is completed.
Hope this helps as I wouldn't consider myself a smarter mind in any case
