Bob's Knobs for Celestron C11 f/10 with Trifid Fastar Secondary Housing and Standard Collimation Screw Threads

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Special Note: The Celestron 11” SCT uses either standard 6-32 or metric M3 collimation screws. Allen, most silver Phillips, and set-style factory collimation screws have standard threads. Most black Phillips 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.
Part: C11stdfst
Fits: Celestron 11” (28 cm) f/10 SCT versions (metal or carbon fiber tube) with standard thread factory collimation screws and "Trifid" rotary cover Fastar secondary housing. Factory collimation screws are silver Phillips. These knobs will also fit the C11 with Starizona Hyperstar (see third photo) only if the collimation screws have standard threads.
Knobs: Black plastic, 16 mm (5/8") diameter
Threads: Stainless steel
Notes:
- These telescopes can have factory collimation screws with either standard or metric threads. Silver Phillips collimation screws are standard thread. Some black Phillips collimation screws are also standard thread. See our hints for more information.
- The factory dust cover will fit normally with Bob’s Knobs installed.
- The rotary secondary cover must remain open when the knobs are installed. The cover is cosmetic only and will not affect operation of the telescope.
Other Information
- Country of Manufacture: United States
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.
Part: C11stdfst
Fits: Celestron 11” (28 cm) f/10 SCT versions (metal or carbon fiber tube) with standard thread factory collimation screws and "Trifid" rotary cover Fastar secondary housing. Factory collimation screws are silver Phillips. These knobs will also fit the C11 with Starizona Hyperstar (see third photo) only if the collimation screws have standard threads.
Knobs: Black plastic, 16 mm (5/8") diameter
Threads: Stainless steel
Notes:
- These telescopes can have factory collimation screws with either standard or metric threads. Silver Phillips collimation screws are standard thread. Some black Phillips collimation screws are also standard thread. See our hints for more information.
- The factory dust cover will fit normally with Bob’s Knobs installed.
- The rotary secondary cover must remain open when the knobs are installed. The cover is cosmetic only and will not affect operation of the telescope.
Special Note: The Celestron 11” SCT uses either standard 6-32 or metric M3 collimation screws. Allen, most silver Phillips, and set-style factory collimation screws have standard threads. Most black Phillips 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.
Part: C11stdfst
Fits: Celestron 11” (28 cm) f/10 SCT versions (metal or carbon fiber tube) with standard thread factory collimation screws and "Trifid" rotary cover Fastar secondary housing. Factory collimation screws are silver Phillips. These knobs will also fit the C11 with Starizona Hyperstar (see third photo) only if the collimation screws have standard threads.
Knobs: Black plastic, 16 mm (5/8") diameter
Threads: Stainless steel
Notes:
- These telescopes can have factory collimation screws with either standard or metric threads. Silver Phillips collimation screws are standard thread. Some black Phillips collimation screws are also standard thread. See our hints for more information.
- The factory dust cover will fit normally with Bob’s Knobs installed.
- The rotary secondary cover must remain open when the knobs are installed. The cover is cosmetic only and will not affect operation of the telescope.
Other Information
- Country of Manufacture: United States
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Bob's Knobs for Celestron C11 f/10 with Trifid Fastar Secondary Housing and Standard Collimation Screw Threads


















