Special Note: The Celestron 9.25â SCT uses either standard 6-32 or metric M3 collimation screws. Allen and set-style factory collimation screws have standard threads. For Phillips collimation screws, most silver screws are standard and most black screws are metric. See our hints for more information.
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 9.25" (23.5 cm) f/10 SCT versions with metric screw threads (CPC 925). Not for C9.25 with "Trifid" Faster or EdgeHD optics (see Item C9.25fst instead).
Knobs: Black oxide steel, 12 mm (1/2") diameter
Threads: Black oxide steel
1. Black Phillips factory collimation screws usually have metric threads, but some black Phillips screws have standard threads. Our hints will help you determine which screws are on your telescope. Make sure the knob threads match the factory screw threads before installing the knobs.
2. These knobs sit inside the tall lip around the perimeter of the secondary, so they may be hard to grasp with two fingers. Adjustments can be made using a thumb or finger against the inside edge of the knob.
3. The factory dust cover will fit normally with Bob's Knobs installed.
4. If your telescope has a factory-installed plastic cap over the collimation screws, it 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.