I have a Ritchey-Chrétien 8 inches, an ASI2600mm, a ZWO EFW Filter wheel (7 x 36 mm), an OAG-L and a focal reducer CCD47. I just purchased a Pegasus Astro Falcon Rotator V2. How I should install all this to have the right backfocus and how many extension rings I need between the telescope rear cell and the focuser ? Thanks for your answers.
Pegasus Astro Falcon Rotator V2
I have my falcon rotator on my Skywatcher Esprit 120. I had to place my Falcon rotator in front of the field flattener (between the scope and field flattener) so that I still had enough back spacing to fit in my OAG-L, ZWO EAF (7 x 2") and the ASI2600mmPro. For my situation I needed a Female M74 to Male M54 and a Male M54 to male M65.
I'm not sure what sized connection you have for the back of the RC 8 inch.
If it helps any, I did a video on connecting mine up https://www.youtube.com/watch?v=eMVset0h03w&t=168s
Cheers
Logan
I'm not sure what sized connection you have for the back of the RC 8 inch.
If it helps any, I did a video on connecting mine up https://www.youtube.com/watch?v=eMVset0h03w&t=168s
Cheers
Logan
Helpful
Thank you very much, Logan !
If your rotator prevents you from getting the proper backspacing to your sensor, I would recommend putting the focal reducer/field flattener after the rotator. That way, you can get correct backspacing against your sensor. Not a pretty sight but it works well! Form follows function… From there, you can work out the length of your extension rings before your rotator to get correct focus. Good luck and clear skies!
Norm
Norm
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I installed this recently on my TOA-130. In my setup I decided to put this before the flattener/reducer so that it wouldn't impact the backspace requirements of the flattener/reducer. There was enough draw tube space when racked out to reach focus, that I could afford to take up 20mm worth of that distance and still reach focus.
In your setup I would try this first to see if you can still reach focus, otherwise you'll have to put it after the reducer, in which case you're eating up back focus spacing and might have to lose the OAG or something if you can't get the precise back focus requirement for your reducer.
In your setup I would try this first to see if you can still reach focus, otherwise you'll have to put it after the reducer, in which case you're eating up back focus spacing and might have to lose the OAG or something if you can't get the precise back focus requirement for your reducer.
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It should make sense to use the following arrangement:
rotator - flatner - oag - fw - cam
If the distance between flatner and cam is too large then:
rotator - oag - flatner - fw - cam
but be careful that the rotator and oag do not collide
br and cs
Hampo
rotator - flatner - oag - fw - cam
If the distance between flatner and cam is too large then:
rotator - oag - flatner - fw - cam
but be careful that the rotator and oag do not collide
br and cs
Hampo
Here's an example of placing the rotator before the field flattener. Not the best looking set up but it works perfectly! ;-) Good luck and clear skies!