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: Most Celestron 8" (20 cm) f/10 SCT made in 2005 and later with black Phillips factory collimation screws that have metric threads. Includes SkyWatcher SCT and non-EdgeHD Fastar.
Knobs: Black oxide steel, 12 mm (1/2") diameter
Threads: Black oxide steel
1. Most models with black Phillips factory collimation screws require metric knobs. A few post-2005 scopes have black Phillips collimation screws with standard threads. Here are some hints to help determine which screws your telescope has. Make sure the knob threads match the factory screw threads before installing the knobs. More information is in our Celestron Technical Paper.
2. These knobs will fit the metric Fastar version only if it does not have EdgeHD optics. Scopes with EdgeHD optics require different knobs (Item C8edg).
3. The factory dust cover will fit normally with Bob's Knobs installed.
4. Some telescope versions have a small plastic cover over the factory collimation screws. This cover 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.