STXL Backfocus

[niharika]

Hi,
Does anyone know the optical back focus distance of STXL11002 with Self guiding filter wheel? SBIG documentation indicates optical backfocus with 3mm filter to be 2.357" where Planewave adapter documentation indicates something different.

Thank you
Raki

[Paul Haese]

The STXL 11002 with integrated filter wheel has a backfocus of 61.84mm. Just recently found this out myself;).

[niharika]

Thanks Paul,
I have the following information so far according to the STXL Operating manual which matches your comment

Mechanical
===========================
STXL Body Only = .997" = 25.31
STXL + FW8G = 2.435" = 61.84

Optical with 3mm filters
======================
STXL Body Only = .958" = 24.33mm
STXL + FW8G = 2.357" = 59.87mm

My understanding is this measurement is without the mounting plate adapter. And following is the unverified information that I have from SBIG group which probably needs to be added to the above if I want the adapter to be threaded in.

"The lip inside the threaded part of the STX mounting plate is .050"
[1,27mm] "


I am waiting for a reply from SBIG as I don't intend to get my calculation wrong.

Regards
Raki