Side by side mounting plate

Bruce Donzanti

I think I am going to try and mount my Sky-Watcher Esprit 120mm with my C11” where I am currently using a piggyback design with an 80 mm. My set up requires it to be in park 4 in my ROR observatory for it to close.  I understand that side by side is a better design.  Any recommendations on the best side by side mounting plate to use? 



I use the SBD18SS that AP sells, riding in a DOVELM162, with a C14 on one side in another DOVELM162, and a 6”f9 on the other side in an ADM TGAD, for which I made a custom riser plate. I’ve thought about replacing the TGAD with another DOVELM16, and shimming to get collimation, but the flexure in the TGAD has been acceptable for my visual use. 


M Hambrick

Hi Bruce

I switched from piggyback to tandem arrangements for all of my imaging and guide scope combinations hoping that doing so might reduce or eliminate what I believe to be differential flexure in some of my images.

For my tandem arrangement I have a DOVELM162 attached to the Declination top plate on my 1100GTO mount as the base dovetail slide. Then I have a SBD13SS attached to the DOVELM162 base, with another DOVELM162 to which the imaging scope is attached, and a DOVEDV10 for the guide scope. The sketch below shows the arrangement with the dimensions that balance the arrangement for my 180 EDT setup.

Although I did not see any significant reduction in the differential flexure, I did find that the tandem arrangement makes it possible to more precisely balance the scopes. Roland has some good instructions on the A-P web site for balancing a tandem setup. The most important step being to do some or all of this procedure indoors during the daytime so that you can see what you are doing.


Bruce Donzanti

Thanks for the excellent info and diagram, Mike!