I just bought an ONTC 8" with a 3" focuser from TS. And I am consider to add a coma corrector for the imaging.
However, the length of drawer is only 3.5cm which seems not support to TV Big paracorr because it will shift focus length 73mm outwards.
May I can only use 1.0x Riccardi Design or TS-Optics NEWTON Coma Corrector 0.85x Reducer.
Is there any comparsion of them or some solution to use Big paracorr?
I don't think you need Big paracorr. This will significantly ruin your wallet and reduce the f ratio of your device.
If your corrector is a SharpStar 3" 0.85x (I know TS likes to rename Chinese brands) then this is a good corrector.
Table from SharpStar. I hope this helps you.
Ps Yes, I wanted to add. That the telescope on the link is not Chinese. If that and not USA. The photo was taken 40 kilometers from the metropolis.
Edited by a__l, 22 March 2023 - 05:33 PM.