Bob's Knobs Collimation Knobs for Celestron CPC1100 with Fastar
Fits: Celestron 11" (28 cm) f/10 SCT versions with Fastar and metric M3 screw threads (CPC 1100). It is important that you choose the correct style Bob's Knobs for your telescope. Please note the number and type of screws on your secondary housing before ordering. The CPC 1100 SCT requires knobs with metric threads. The CPC 1100 secondary can be identified by a factory-installed plastic cap over the collimation screws. This cover must be removed and set aside when Bob's Knobs are installed. The cover is cosmetic only and will not affect operation of the scope. Celestron 11 inch SCTs manufactured prior to 2006 had standard 6-32 collimation screws. Do not use metric knobs on those telescopes.