Hi All,
Just pointing out that even adding a small extra load on the mount can end up putting upto twice the weight of the added pay load. Sorry about the detail!
Out of balance loads will wear the gears much faster and make backlash problems even worse.
Putting the main 'scope off axis with the guide scope to the side will mean making a heavy mounting plate to carry the guide 'scope. Adjustment must be made to rebalance the outfit quite accurately. You will find that the main scope will be moved about 50 mm off centre to balance the guide scope.
To reduce weight one suggestion would be to reduce the size of the guide scope - generally a 150mm to 300mm focal length (depending on the guiding CCD) guide scope will guide to better than 1 pixel. If you have a fancy CCD (which I don't) like an Sbig ST4 you may get away with a 50mm to 100mm focal length guide scope. Guide scope diameter need only be 60 to 80mm (max).
Kind Regards,
Jerry.
