I have a Celestron 9.25" SCT on a fork arm and I use a Celestron wedge to polar align for taking photos. I was looking into buying a flip mirror to ease my life when using the go-to with a camera attached. The camera is a LUMIX G1 DSLR which will only pass through for my eyes the brightest stars and certainly not nebula. The go-to works fine but does not always deliver the target where I want it in the field of view. I do all what I think are the usual things and take 10 second exposures to check target locations and focus before committing to imaging. Having researched flip mirrors I am now uncertain having read about "back focus" and problems with eyepeice/camara par-focus problems. I would appreciate any advice the membership has on this subject. cheers.

Hi, I have an 11" SCT and have used a flip mirror and camera (a Lumix GH1) without any problems. Some details of the setup are on old thread on this forum (www.irishastronomy.org/index.php?option=...&id=96887&Itemid=211). My understanding is that back focus is rarely an issue with the SCT design, and I didn't run into any difficulty. If you are based in the Dublin area, you are welcome to borrow my flip mirror to check that it will do the job for you.

Mike

Hi,
I use 2 SCT's and both have zero issues with backfocus using a star diagonal.
The fact that the primary mirror moves for focusing means that you can actually change the focus location by refocusing, so you should always be ok on a SCT.
This doesn't hold true for refractors and dobs.

Notice from your description on changing scopes that you used a vixen flip mirror. That is described in sales sources as 2" focus fit flip mirror with a push fit - does that mean I couldn't use it on my 9.25 Celestron SCT which takes 1.25 fittings or am I showing my inexperience here and it would fit anyway? cheers

You would need an adapter that would screw onto the abck of the SCT, replacing the 'visual back' that comes as standard, and allow you to use 2" accessories. Such adapters are readily available (e.g. www.teleskop-express.de/shop/product_inf...-2--accessories.html) and would also allow you to move up to a 2" diagonal if you wanted to use 2" eyepieces. You may find that adding accessories costs almost as much as th etelescope itself. :S

Mike

Thanks for that - as for accessories - they could pay for my funeral at this rate !