Skip to content

Covid-19 Update - We're Shipping! We're Here For You!

Bob's Knobs Collimation Knobs for Celestron Pre-1980 Orange SCT - C8ORG


Bob's Knobs Collimation Knobs for Classic Celestron C8 Orange SCT

These 13 mm (1/2") wide black plastic knobs with black anodized aluminum alloy threads will fit vintage orange tube Celestron C8 SCT models manufactured before 1980. The secondary mirror on the classic Celestron 8" SCT contains three factory set-style collimation screws along with a fourth central screw in the secondary housing. Includes two sets of knobs each with distinct screw lengths to accommodate your telescope. Two or three screw thread turns should be above the secondary housing. The dust cover should fit without touching the knobs.

Note: The Celestron 8" Schmidt-Cassegrain employs collimation screws that are either standard 6-32 or metric M3. Factory set-style collimation screws, such as the ones on the classic orange Celestron C8, have standard threads.