Quality of image when using a 0,67 reducer of a 8 or 10 inches RC telescope ?

Equipment Ritchey-Chrétien Reducer
4 replies•184 views
Jérémie avatar
Jérémie avatar
Hi All, me again.

This time seeking feedback from fellow astrophotographers using a focal reducer of 0,67 on their RC scope (8 to 10 inches - 200 to 254mm) with usually a FD of 8 (so between 1600 and 2000 focal length).

Are you happy with quality of your images on all the image circle with your focal reducers ? With large sensors of course…

Any « proofs » ? ´Links to images are welcome to judge ! :-)
Michael Timm avatar
Michael Timm avatar
Hi @Jérémie Ochin ,

i am often using a AstroPhysics CCDT67 on my RC8. Unlike other reducers the CCDT67 is not so sensitive when it comes to the right spacing, so i do not care much about it. The quality is good in my eyes - though i do not do star peeking at all corners. I am also using a Ricardi Reducer for my APO, which is way more sensitive.

You can check for example my crescent nebula, it was taken at about 0.72:

NGC 6888, Crescent Nebula

You can check the distances here:
CCDT67 Distances@AstroPhysics

CS
Michael
Helpful Concise Supportive
Jérémie avatar
Jérémie avatar
Michael Timm:
I am also using a Ricardi Reducer for my APO, which is way more sensitive.

Thanks a lot for your feedback Michael. Indeed, seems to work pretty well ! I also see you use a reducer / flattener on your Photoline APO.

I have a 71/347 from TS Optics as well, but flattener is included. I was also wondering if I could use a focal reducer without introducing abberations or field curvature (because it is already corrected and I guess reducers / flatteners may not be conceived for that purpose). I have a very small sensor and would be happy if I could reduce the focal length as well on this quadruplet.

@Michael Timm  Do you have any input on that (though it was not the intial topic ).

Thanks !
Michael Timm avatar
Michael Timm avatar
I do not think that it makes sense to add an additional reducer / flattener on a already reduced / flattened setup, but i am not an expert on this topic. I would suggest that you ask TS directly - they know their telescopes well and - in my experience - respond very quickly to questions.
Jérémie avatar
Jérémie avatar
Michael Timm:
I would suggest that you ask TS directly

That's done
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