Adjustment screws for the rear mirror of a 6 inch SCT | Bob’s Knobs

A 6-inch Schmidt-Cassegrain is compact and easy to carry, but the small collimation screws on the secondary holder are difficult to operate, especially with gloves on. These adjustment screws for a 6-inch SCT from Bob’s Knobs replace them with larger knobs that you twist with your fingers.

First, check that your telescope is a 6-inch Schmidt-Cassegrain with the usual collimation screws on the secondary holder. This type of viewer can be found in the catadioptric telescopes.

Replace the screws one by one so that the mirror remains in place. Then adjust the collimation to a bright star at high magnification, or with a artificial star for collimation, with increasingly small turns.

If you have a Celestron C6 f/10 with metric thread, there is a set specially designed for the C6.