Bob's Knobs for Celestron C8 f/10 Pre-1980 Orange-Tube Secondary # C8org

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.

Part: C8org

Fits: Pre-1980 Celestron 8” (20 cm) f/10 SCT with orange optical tube and factory set-style collimation screws. These screws can be either Allen or slotted.

Knobs: Black plastic, 13 mm (1/2”) diameter

Threads: Black anodized aluminum alloy

Notes:

1. These knobs will fit orange tube (second photo above) C8 models made prior to 1980. The secondary has factory set-style collimation screws (third photo above) 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 (fourth photo above) and the dust cover should fit without contacting the knobs.
3. Do not adjust the center screw; this is the secondary pivot screw.