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Piggybacking refractor without rings

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#1 MikeBOKC

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Posted 15 January 2013 - 09:43 AM

OK I sometimes piggyback a small refractor on my CPC1100. Have the Losmandy D plate on top and the counterweight system underneath. In the past I have used the standard adjustable rings. Recently I modified my TMB92L to piggyback my PST alongside for dual solar viewing, run on an AT Voyager, but with the addition of the extra dovetail, the rings and all the TMB is just a bit morer weight than is convenient to plunk on top of the CPC and balance. When I do get balanced the refractor focus tube protrudes over the CPC eyepiece too much. Hence I am considering a Skywatcher 80ED or something similar in the 5 pound range to replace it as my piggyback refractor.

I may go with rings mounted on the Losmandy D plate adaptors, but that is a hassle to slide on, and a bit heavier than I want. I have a couple of these Vixen adaptors:

http://www.astronomi...vixen-black_...

I have test mounted these upside down on the Losmandy D plate adaptors, then atop the D plate, all of which could remain in place atop the CPC for easy mounting of the smaller refractor by just sliding its Vixen plate into the assembly. Testing the TMB by simply sliding its Vixon plate into the piccyback assembly (which has no adjustable rings if you get that picture) I can get objects in the field fo view but well off to the side. I hate to go back to rings for precise alignment of the refractor, since that's another cuople of pounds and more expense, not to mention extra hassle every time I load up. Has anyone had success piggybacking a refreactor without rings by shimming the Vixen plate to get it better centered in alignment with the big scope's optics? I don't need perfect centering as this is a visual setup only . . . just good enough to get objects in the field of view of both scopes without the added hassle of hauling a full ring/plate assembly and getting it all rigged on top every time I set up.

#2 snowboycosmos

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Posted 29 January 2013 - 11:42 AM

My AT72ED just arrived. I'm wondering now how to piggyback it. Can the CPC1100's tracking function with all that weight? what's the best solution ?

#3 MikeBOKC

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Posted 29 January 2013 - 01:31 PM

Well the best ans easiest way is to get a set of 90mm rings which are mounted on Losmandy D plate adaptors and install a Losmandy D plate on top of the OTA. You wil then need a comparable counterweight assembly for the bottom to address the balance issues. Once all assembled it will track and go to well. You might give Astronomics a call re the hardware you will need.

#4 Motokid600

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Posted 02 February 2013 - 04:05 AM

My AT72ED just arrived. I'm wondering now how to piggyback it. Can the CPC1100's tracking function with all that weight? what's the best solution ?


I have a 72ED on my CPC11 as well. It tracks great as long as you have a nice balance. I dont use rings. I ditched them once i got my auto guider. Couldnt stand adjusting the rings to get a guide star. Ive been using ADM so i got a D series dovetail and a max guider. It hooks up with the plate the APO came with and is solid as could be.






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