So, what are my options for a focal reducer

[telemarker]

I have an ED100 but would also like to have the option of a faster scope with a wider field of view for some astro photos. I was hoping for something to bring it down to F6 or there abouts. I know Vixen make a 0.67x FR. Are there IISers who have tried this or could recommend a reducer that would work with this scope?

PS I would also have to have a flat field.

Keith

[Gama]

I have read users using the Celestron/Meade f6.3 reducer with adapters.
Results where very good, and cheap.

Theo.

[gbeal]

While I am not suggesting Theo isn't right, it was always my belief that a refractor needed a reducer or flattener that was sort of "designed" for a refractor. The SCT versions correct and reduce, correcting the problems that are inherent with the SCT design.
In my case, I use an AP67 CCD Telecompressor, and this is my refractor(s) as well as my Maksutov.
Best option if you can is to try one or two. There will be a glut of SCT styles out there, borrow one, and try it.
Gary

[telemarker]

Thanks Theo and Gary, the main problem is having access to gear to borrow. Think I'll bite the bullet and go with the meade 6.3. I already have a SCT that would benefit from one of these anyways. Thanks again for your help guys :thumbsup:

Theo, you mentioned adaptors :shrug: could you elaborate pls

regards
Keith

[Gama]

Yes, you need the SCT thread to 2" nose, etc. Converts the threads so you can use it in your focuser..
Anyway, go here cause its very similar to what you are after.. http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2126277/Main/2123746

Go wild !.


Theo.

[Merlin66]

According to the guys in the UK, the WO frII works better than the SCT reducer on the ED series....

Ken

[bert]

I have the Vixen ed103 rerfractor and official reducer, (f7.7 to 5.1ish)It fits the uncommon vixen drawtubes, and I'm pretty sure they are a pita to fit up to another drawtube. It also vignettes to hell, flats are a must.

Rumours I have heard is go for the William optic 2. I'm pretty sure there was a thread on it on iis about not so long ago.

Brett

[Kal]

Gary,

I believe that the only correcting that the common SCT F6.3 reducer/corrector does is flatten the field. By flattening the field, you reduce the amount of coma that you see in an SCT.

If you look at these results (http://ghonis2.ho8.com/052308AT127mmfocaltests.html) with a 127 triplet refractor and compare the F6.3 reducer/corrector to a televue 0.8 reducer/flattener you can see that it performs pretty well.

[Merlin66]

That's why the "old" SCT reducers don't appear to work well on the "new" ACF models; these ACf's have already been corrected for field curvature with the built in corrector... adding an "old" reducer just adds a negative curvature back in.

[Kal]

The meade ACF's are corrected for coma. They still have field curvature, although less curvature than an SCT. The meade ACF doesn't have a built in corrector either, although the new celestron edgeHD's have a built in corrector.