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Prim-Focuser/Korrektor Cassegrain

The Primary Focuser of the ASA/Keller Cassegrain is located in f3/1200mm. It is driven by a Faulhaber motor and linked to an encoder all triggered by a SmartFocus controlbox and software.

The Primary Corrector (diagram by P.Keller): For fast speed and huge fields. The prime focus is permanently installed in front of the secondary mirror and by removing the secondary in its holder you allow the light path to reach the prime focus.
Switching between the 2 focal configurations takes only 1 minute. The spot diagram shows a field diameter of 64mm, so you are ready even for very large CCD's with this telescope. The backfocus is 79.31 mm measured from the front of the lensring.
For the SBIG ST10XME the 79.31mm are reached by (5mm Frontring+25.5mm f3-Adapter+7.2mm Spacerring distance on 2-Zoll Adapter+24mm Filterwheel+17.6mm SBIG-CCD distance)