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RPF-2804 Flattener - Does It Bring Focus Forward?

Started by SJJindra, 01/25/2006 01:15PM
Posted 01/25/2006 01:15PM Opening Post
I have a permanently mounted imaging setup including an FS128, FS78, and FS60 mounted in an over/under fashion on a CI700 mount. I have an SXV-H9 imager (with filter wheel) and SXV guiding camera that I attach to either of the OTA's depending on the target. I have the Tak focal reducers for imaging at F6 (F4.5 on the FS60). At times I would like to image at the full focal ratio (F8.1 and F6) of the scopes, but the trouble of adding the extentions and rebalancing everything is prohibitive.

I have a few questions about the RPF-2804 (Ranger/Pronto Field Flattener:

Are the threads female "T" threads to the front and male "T" threads to the rear? If not what threads are there?

Does the flattener bring the point of focus to the front, closer to the focuser of the OTA. If so, by how much (based on your Pronto or TV-85)? If it does, this would allow me to image at full for or slightly greater focal length without major rebalancing and would keep the optical train more rigid.


Steven Jindra
Deer Park, Texas
Posted 01/25/2006 02:50PM #1
I just spoke with a gentleman at Televue (I failed to remember his name) who answered my questions on the RPF-2804 flattener. The answers are:

It does have female "T" threads front and male "T" threads back.
It does not bring the point of focus forward more than an inch or so. So it does not sound as if it will work for my purpose.

Steven Jindra