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Quote:As I said earlier, ONAG back focus is 66mm which is quite long. My camera BF is 14mm, filter wheel is 29mm, ONAG SCT adapter is 6mm, that gives an absolute minimum total back focus of 115mm. I think it will be closer to 120mm.105mm back focus will work with my existing Hutech OAG. But the biggest inconvenience is taking apart the imaging equipment every time I change focal ratio. Celestron C-11/C-14 EdgeHD FR does not require changing back focus with or without FR. It seems to be implied by Celestron that they will maintain the same BF for C-8 EdgeHD but they didn't.I am not using T-adapter. My understanding is you are planinng to use T-adapter.Peter
Quote:From Celestron's web site description of their new focal reducer, it still looks better than Optec focal reducer. The imaging circle appears to be bigger than Optec. Celestron FR supports APS-C sensors which is a pretty good size CCD sensor. Plus Optec uses dovetail connection instead of SCT threaded connection. I prefer SCT threaded connection.
Quote: Optec FR has one side SCT thread, but not the other side. The other side is still a dovetail connection which requires Optec custom adapter
Quote:The back focus is 105mm from the back side (not front side where it meets the scope) of focal reducer. It does not include the length of the focal reducer itself.You can fit the T-adapter in between FR and OAG/camera but you will most likely have to unscrew the second half of T-adapter to meet your BF requirement.Peter
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Quote:Uhhh... what's CES?
SVR90 Raptor QHY9C OSC Camera ZEQ25 EQ Mount Porta II Alt-Az
Quote: This one shows a picture of Optec's custom adapter for DSLR. Notice the dovetail at top (set screws).
Quote: Is this the Optec reducer model you and Peter are talking about?
Quote: Quote: This one shows a picture of Optec's custom adapter for DSLR. Notice the dovetail at top (set screws). I don't think that's a 'dovetail' on the tube side. The three set screws are tightened down into the dovetail on the focal reducer itself. This arrangement allows multiple cameras with different back focus distances to be used with the focal reducer. How is Celestron taking care of this? You will still have to buy some kind of tube to attach to the Celestron f/r. It may not be as expensive, but you'll have to have something. I agree that backing out three set screws to change/remove a camera is not the cleanest solution.Patrick
Quote:t's very strange how Optec assumes people won't put anything in between FR and camera like OAG and filter wheel.