Great thread ( https://www.cloudyni...-focal-reducer/ ) started by Russ on his WO binos which sparked this question in my mind. Eddie gave all the necessary tools to analyze the impact of SA and aperture and contrast loss when increasing the optical path. I have the following equipment:
1. Denk II = 115mm of backfocus
2. Powerswitch = ~15mm
3. 2” meade 5000 dielectric diagonal with VB = 133mm
4. Standard Celestron 1.25” diagonal with VB = 100mm
5. Denk multipurpose OCS.
6. Denk 2” and 1.25” nosepiece adapters
7. Celestron C8. 2000mm focal length.
I am trying to use what I have to mainly view planetary but sometimes DSOs as well. Also my budget is pretty tight so buying a T2 system to lower the optical path is not feasible.
I have read that putting the OCS on the nosepiece of the diagonal improves backfocus. Does this mean that it reduces the optical path and thus doesnt reduce aperture or contrast? Does using an OCS on the nosepiece also not increase SA?
My other option would be to use the standard 1.25” diagonal with the Denk 1.25” adapter. I would lose the ability to use the OCS but would gain 33mm in backfocus. (Meade diagonal - celestron diagonal).
Any advice and suggestions are greatly appreciated.
Edited by miamichillin99, 22 May 2019 - 07:41 AM.