Posted 19 September 2012 - 09:04 PM
If you meah the difference between home positions between side by side by side and piggy back, the top puck is easy to orient. To get a home position appropriate to a side-by-side setup, there are three small hex screws on the side of the mount head up near the top puck. Position the empty mount head in DEC so that the center line of sight for the polar scope is clear. Loosen the the hex screws just a little and rotate the puck dovetail slot to east-west. Then tighten the three hex screws firmly. Now the dovetail holding the pair will point them north for the side by side setup. and the sight line through the polar scope is open.
Having the dovetail in the top puck oriented so that the telescope(s) point to 0/360 azimuth helps me do a two step iterative polar alignment and has the sight line for the polar scope open if you polar align using the polar scope.
Mine is a single 10" SCT with a Losmandy dovetail and Ken Dauzat saddle plate, so my dovetail slot faces north-south but I've set up alongside folks with side by side scopes with the dovetail slot oriented east-west to get a Home position that has the scopes pointed North and the polar scope open for use.