Bob's Knobs Celestron C8 pre-1980 Orange Tube Collimation Knobs

Bob's Knobs Celestron C8 pre-1980 Orange Tube Collimation Knobs

  (1 Review)
✓ 2 year warranty


2x in stock shipped 1-2 working days

About this product

Model:  bk_c8org
Part Number:  C8org

Bob's Knobs are the BEST option for tool-free collimation.

Simple to fit and easy to use.

Collimate your telescope without an Allen key or screwdriver!

Instructions are supplied but can also be found online as well as useful FAQ.

Images are representative and may not show the exact knob size / threads.

IMPORTANT: Please ensure the Bob's knobs threads and factory screw threads match before installation.

Knobs for C8 f/10 Pre-1980 Orange-Tube Secondary

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 anodised Aluminium 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.

Customer reviews

Average Rating (1 Review):  
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collimated at last
22 December 2020  | 

OK so maybe I found that my scope is post-1980, not pre, and so the knobs were then a bit long but nothing a couple of washers cant fix.
So much easier than using an Allen key to colimate as well


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