Bob's Knobs

Bob's Knobs allow tool free collimation of the secondary mirrors of Schmidt-Cassegrain and many Dobsonian telescopes.

- Secondary Knobs for Orion and Sky-Watcher Dobsonians 30 mm
- These knobs with 30 mm screws replace the set factory secondary mirror collimation screws on Orion and Sky-Watcher Dobsonian telescopes. read more...
- Our price: $20.95
- Celestron C8 f/10 with Metric Threads
- These knobs fit most Celestron C8 made in 2005 and later with black Phillips factory collimation screws; not for Fastar or EdgeHD models. read more...
- Our price: $20.95
- Celestron C6 f/10 with Metric Threads
- The knobs will fit all versions of the Celestron 6” Schmidt-Cassegrain secondary. read more...
- Our price: $20.95
- Sky-Watcher Dobsonian Primary
- Primary mirror collimation knobs for Sky-Watcher Newtonian (Dobsonian) telescopes with factory collimation screws. read more...
- Our price: $25.95

- Celestron C11 f/10 with Flat Secondary and Metric Threads
- Fits Celestron C11 f/10 SCT versions with flat secondary housing and black Phillips collimation screws. read more...
- Our price: $20.95

- Sky-Watcher Dobsonian Primary
- Primary mirror collimation knobs for Sky-Watcher Newtonian (Dobsonian) telescopes with factory collimation screws. read more...
- Our price: $25.95
- Celestron C11 f/10 Fastar with Metric Threads
- Fits Celestron C11 with Fastar secondary housing and black Phillips factory collimation screws. read more...
- Our price: $22.95
- Celestron C9.25 f/10 EdgeHD and Fastar
- These knobs fit Celestron C9.25” f/10 EdgeHD and Fastar optical tubes with the triffid style secondary mirror housing. read more...
- Our price: $22.95

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