Collimate your Catadioptric or Newtonian reflector style telescopes without tools!
It's easy...just grab a Bob's Knob collimation thumbscrew and turn. You can even do it while looking through the eyepiece on most scopes. These thumbscrews are also much easier to use with gloves on. And perhaps most importantly, you'll never drop that pesky little Allen wrench or screwdriver into the grass again. Installation is a snap with the included instructions, and you can undo the modification at any time.
Fits: Celestron 8" (20 cm) f/10 SCT with orange optical tube and factory set-style collimation screws.
Knobs: Black plastic, 13 mm (1/2") diameter
Threads: Black anodized aluminum alloy
1. These knobs will fit orange tube C8 models made prior to 1980. The secondary has factory set-style collimation screws with a fourth central screw in the secondary housing.
2. Two sets of knobs, each with a different screw length, are included with your order. Use the length that fits your telescope best. There should be two or three screw thread turns above the secondary housing and the dust cover should fit without contacting the knobs.