Bob's Knobs: Collimate your Schmidt-Cassegrain or Newton-Telescope 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. And 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.
These knobs will fit most Newtonian reflectors made by Guan Sheng Optical, including GSO, Hardin Optical, Meade Lightbridge, and Zhumell models. They have a screw diameter of 7 mm (collimation) and 6 mm (locking), and will usually fit your telescope if you select the knobs that match your scope’s aperture.
Primary collimation
- Knobs: Black plastic, 30 mm (1-1/4”) diameter, 5-point fluted
- Threads: Plated steel
Primary Lock
- Knobs: Black plastic, 25 mm (1”) diameter, knurled
- Threads: Stainless steel
These knobs will fit telescopes with M7 (7 mm diameter) primary adjustment screws and M6 (6 mm diameter) primary lock screws. These knobs will not fit 8” GSO telescopes that have M5 (5 mm diameter) primary adjustment screws.
The manufacturer Bob's Knobs supplies various collimation screws for Schmidt-Cassegrain, Ritchey-Chrétien and Newton telescopes.
The selection includes screws for primary and secondary mirrors for optics between 5" and 16". In addition, Bob's Knobs offers mounting screws for various mounts from Celestron (CGE, CGE Pro, NexStar), Losmandy (GM-8, G-11) and TeleVue (Gibraltar).
Please refer to the respective specifications and technical data to find the right screws for your model!
