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 C8-N/NGT, C10-N/NGT, Orion Astrograph, Astroview, SkyQuest XX and XT, Skyview, SkyWatcher, StarBlast, GSO, and many others.
Secondary Characteristics: 4-vane spider, a deeply recessed center screw, and factory headless set (grub) collimation screws. The secondary plate holding the screws is about 20 mm (3/4") thick. This is a very common Newtonian secondary configuration.
Knobs: Black plastic, 13 mm (1/2") diameter
Threads: Stainless steel
1. We offer knobs with screws having either 30 mm or 35 mm length. Order knobs with a screw length sufficient to allow the knobs to clear the secondary housing. Knobs with 30 mm screws are the most common in this configuration.