Starizona SCT Corrector IV - 0.63X Reducer / Coma Corrector (Backspace requierments)? - Forums

Topic starter

Dec 22, 2024 · Edited: Dec 22, 2024

SO I have an older C8 and I was encouraged to invest in the Starizonia .63 reducer. Info I found was to establish a back space of 90.3 mm "but at 90.3", the telescope does not focaus clearly. The ASIair can't establish the scopes focal length..
(I doubel checked Collimation with a tri-bahtinov mask) I am using a ASI2600 MC camera.

Question for those who have this Scope, Starizonia reducer and the 2600 camera, what back spacing are you using?
Or do you have any other suggestions to check?
Thanks in advance.

Craig Harding

Dec 22, 2024

90.3mm. The SCT corrector comes with a 35.3mm adapter. So, just configure your camera as if you are doing 55mm backfocus and then add the 35.3mm adapter before attaching it to your reducer.

Bill Griswold

Dec 22, 2024

I have a similar setup with a QHY. I believe 90mm was very close but used an adjustable spacer to get it nailed. Will doublecheck later.
BTw, that reducer on the C8 is actually right around 0.71x. Don't have an ASIAir but if you had to enter the reducer…it may be off.
Bill

Frederic RICHARD

Dec 22, 2024

Je l'utilise sur un vieux C8 (voir mes photos), je l'utilise avec une caméra Atik + roue à filtre et j'ai rajouté un jeu de bague allongé pour atteindre un BF de 90mm en tout, si tu veux plus de détail, n'hésites pas..

Mike H - Sky View Observatory

Dec 22, 2024

I have and use an 1981 orange tube C8. The Arizona reducer would not let the camera come to focus or it was right against the stop. Forget autofocus. I went with the stock Celestron reducer. Although most on AB despise them, I’ve had good success. Stars are round almost to the edge of the field of a 294MC Pro. Autofocus works with NINA.

Mike

Helpful Concise

Ed Litoborski

Topic starter

Dec 22, 2024

90.3mm. The SCT corrector comes with a 35.3mm adapter. So, just configure your camera as if you are doing 55mm backfocus and then add the 35.3mm adapter before attaching it to your reducer.

that's precisely how its set up now

Lynn K

Dec 22, 2024

Age of Celestron C8 shouldn't matter. As far as I know all have F2 primaries with secondaries that magnify x5 to get F10. All have 200mm corrector rendering 2000mm FL. The focus distance distance movement on the baffle tube may vary.

To state the obvious, the 90.3 is from rear of reducer to chip. Did you subtract the backfocus of camera, filterwheel, etc.?

Lynn K.

Helpful Concise

Mike H - Sky View Observatory

Dec 22, 2024

The age of the C8 does matter. That’s why I stated the the type and age. I tried everything including seeking advice from Starizona, Celestron, CN and AB. Apparently it doesn’t have the travel of a more recent unit. Are you thinking I didn’t want it to work? I bought the unit and spent a lot more trying to get it work before I finally sold it to someone who had a newer unit and it worked for him. Please don’t say “it shouldn’t matter” unless you know for a fact. I had the physical pieces and I’m not green. It didn’t work, period.

Mike

Ed Litoborski

Topic starter

Dec 22, 2024

Lynn K:
Age of Celestron C8 shouldn't matter. As far as I know all have F2 primaries with secondaries that magnify x5 to get F10. All have 200mm corrector rendering 2000mm FL. The focus distance distance movement on the baffle tube may vary.

To state the obvious, the 90.3 is from rear of reducer to chip. Did you subtract the backfocus of camera, filterwheel, etc.?

Lynn K.

yes