To answer this question, we need to know the backfocus of your telescope. If it is not given in the instructions, you need to measure it.
Eitherpoint it at the moon and put a piece of of paper behind it, so that you can see a sharp image - the distance between paper and telescope is the back focus. Or, if you already have a focuser, point it at the stars with either a camera attached or star diagonal and eyepiece, and measure the length of your focuser. Pleas note that eyepieces, DSLRs and astronomical cameras all have different optical lengths! A DSLR requires 55mm of backfocus, a CCD-camera often only about 1cm, and a 2" star diagonal about 11cm - so may work with an eyepiece and star diagonal without extensions, while a CCD-camera may require an extension.
The SC-version of the Steeltrack has got a focus travel of 30mm, so if you are switching between a 2" star diagonal and an astronomical CCD-camera, you will require an extension. The possible minimum heights are as follows
as supplied, incl. 2" clamp: 93 mm
with optional S58 direct-thread adapters: 80 mm
The RT-version for refractors may fit too, it has got a longer focus travel of 80mm and the following minimum lengths:
as supplied, incl. 2" clamp: 70 mm
with optional S58 direct-thread adapters: 59 mm
with optional S58-ClickLock clamp: 89 mm
You have to check the manual to see if one of the adapter threads matches your telescope, or if you need to manufacture a special adapter.
The SC version has got a shorter focus travel as you are more flexible with a Schmidt-Cassegrain and its moveable ain mirror than with a refractor telescope.
Answer by: Baader Web Team (Admin) on Aug 3, 2021 11:16:00 AM