Setting Up SC-2 - tech tip

Initial set up of the SC-2 requires one to offset the pick-off mirror into the light path but not so much as to vignette the main imager. Looking from the objective at the imager chip and SC-2 mirror one can verify position without being under the night sky. The main imager should be fully visible from all angles when viewed thru the objective.

The attached photo shows the SC-2 mirror (and CMOS chip reflected in the mirror) as well as an ST-7 shutter. The taking camera was aimed on the optical axis therefore the SC-2 clearance appears more then required. When viewing from the outer edge of the objective, this gap closes and is much tighter.

The interested stugent will derive an equation to calculate the required offset distance given focal length and aperture.

Regards All,

Tim