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Bobs Knobs

Items 1 - 25 of 67

Bob's Knobs Astro Tech Collimation Knobs - Secondary Mirror - AT10RC

SKU: BOB-AT10RC
  • Set of three collimation knobs from Bob's Knobs designed for the Astro-Tech 10" RC telescope's secondary mirror.
  • Measuring 16 mm (5/8") in diameter, these knobs feature black plastic construction.
  • Although the factory supplied dust cover may come into contact with these collimation knobs while they are installed, it will still remain in place.
  • These Bob's Knobs Collimation Knobs contain stainless steel threads.
$27.00 $20.76

Bob's Knobs Astro Tech AT12RC Collimation Knobs - Secondary Mirror - AT12RC

SKU: BOB-AT12RC
  • Set of three collimation knobs from Bob's Knobs designed for the Astro-Tech 12" RC telescope's secondary mirror.
  • Measuring 16 mm (5/8") in diameter, these knobs feature black plastic construction.
  • Although the factory supplied dust cover may come into contact with these collimation knobs while they are installed, it will still remain in place.
  • These Bob's Knobs Collimation Knobs contain stainless steel threads.
$27.00 $20.76

Bob's Knobs Astro Tech AT6RC & AT8RC Collimation Knobs - Secondary Mirror - AT8RC

SKU: BOB-AT8RC
  • Set of three collimation knobs from Bob's Knobs designed for Astro-Tech 6" and 8" RC telescope secondary mirrors.
  • Measuring 16 mm (5/8") in diameter, these knobs feature black plastic construction.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed, although some secondary mirror height differences may cause the knobs to be too high for the dust cover to fully seat.
  • These Bob's Knobs Collimation Knobs contain stainless steel threads.
$27.00

Bob's Knobs Celestron 11" SCT f/10 Metric Collimation Knobs - Black Oxide - C11METBO

SKU: BOB-C11METBO
  • Measuring 12 mm or 1/2" in diameter, these Bob's Knobs Collimation Knobs fit Celestron 11" CPC, EdgeHD, and metric Fastar Schmidt-Cassegrain telescope models.
  • Construction and threads both consist of black oxide steel.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • Some telescopes may contain a small plastic cover over the factory collimation screw which will need to be removed before installing these Bob's Knobs collimation knobs.
$22.00

Bob's Knobs Celestron 11" SCT f/10 Collimation Knobs - Standard Secondary - C11STD

SKU: BOB-C11STD
  • Measuring 16 mm or 5/8" in diameter, this Bob's Knobs Collimation Knob set fits Celestron 11" f/10 Schmidt-Cassegrain telescopes with standard collimation and flat secondary housing collimation screw threads.
  • Made from black plastic with black anodized aluminum alloy threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • These collimation knobs are not compatible with CPC 1100 or 11" EdgeHD telescopes.
$22.00

Bob's Knobs Celestron 11" SCT f/10 Fastar Standard Collimation Knobs - C11STDFST

SKU: BOB-C11STDFST
  • Measuring 16 mm or 5/8" in diameter, these Bob's Knobs collimation knobs fit Celestron standard collimation C11 Schmidt-Cassegrain telescopes with "Trifid" rotary cover Fastar secondary housing screw threads.
  • Made from black plastic with stainless steel threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • With these Bob's Knobs Collimation Knobs installed, it is crucial that the rotary secondary cover remain open.
$21.00

Bob's Knobs Celestron 14" SCT f/11 Collimation Knobs - Standard Phillips - C14STDPHI

SKU: BOB-C14STDPHI
  • Measuring 16 mm or 5/8" in diameter, these Bob's Knobs collimation knobs fit Celestron C14 f/11 Schmidt-Cassegrain telescope models with standard thread Phillips factory collimation screws, whether or not they contain Fastar.
  • Made from black plastic with black anodized aluminum alloy threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • These Bob's Knobs Collimation knobs are not compatible with Celestron C14 SCTs with EdgeHD optics.
$22.00 $16.76

Bob's Knobs Celestron 14" SCT f/11 Collimation Knobs Set Screw - C14SET

SKU: BOB-C14SET
  • Measuring 19 mm or 3/4" in diameter, these Bob's Knobs collimation knobs fit Celestron C14 Schmidt-Cassegrain telescopes that have factory headless set-style collimation screws, including those with Trifid Fastar secondary housing.
  • Made from black plastic with black anodized aluminum alloy threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • With these Bob's Knobs Collimation Knobs installed, it is crucial that the rotary secondary cover remain open.
$21.00

Bob's Knobs Celestron 5" SCT f/10 Metric Secondary Collimation Knobs - Black Oxide - C5METBO

SKU: BOB-C5METBO
  • Measuring 12 mm or 1/2" in diameter, these Bob's Knobs collimation knobs fit Celestron 5" f/10 Schmidt-Cassegrain telescopes manufactured in 2006 or later that contain black Phillips factory collimation screws.
  • Construction and threads both consist of black oxide steel.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • Some telescopes may contain a small plastic cover over the factory collimation screw which will need to be removed before installing these Bob's Knobs collimation knobs.
$22.00

Bob's Knobs Celestron 5" SCT Collimation Knobs Standard Secondary - C5STD

SKU: BOB-C5STD
  • Measuring 13 mm or 1/2" in diameter, this Bob's Knobs Collimation Knob set fits Celestron 5" f/10 SCTs with silver Phillips, silver Allen, or black Allen factory collimation screws.
  • These collimation do not offer compatibility with telescopes featuring black Phillips factory collimation screws.
  • Made from black plastic with black anodized aluminum alloy threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • Some telescopes may contain a small plastic cover over the factory collimation screw which will need to be removed before installing these Bob's Knobs collimation knobs.
$21.00

Bob's Knobs Celestron 6" SCT Collimation Knobs Secondary - Black Oxide - C6BO

SKU: BOB-C6BO
  • These Bob's Knobs Collimation Knobs fit all versions of the Celestron 6" f/10 SCT.
  • Each collimation knob in this set measures 12 mm or 1/2" in diameter.
  • Construction and threads both consist of black oxide steel.
  • The factory supplied dust cover will fit most versions of this design with the exception of some earlier variants with these collimation knobs installed.
$22.00

Bob's Knobs Celestron 8" EdgeHD Collimation Knobs - Black Oxide - C8EDGBO

SKU: BOB-C8EDGBO
  • Measuring 12 mm or 1/2" in diameter, these collimation knobs from Bob's Knobs fit Celestron 8" f/10 Schmidt-Cassegrain telescopes with EdgeHD optics and Fastar.
  • Construction and threads both consist of black oxide steel.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • These collimation knobs are not compatible with 8" SCTs with Fastar secondary that do not have EdgeHD optics.
$22.00

Bob's Knobs Celestron 8" SCT Hyperstar Secondary Collimation Knobs - Black Oxide - C8HYPBO

SKU: BOB-C8HYPBO
  • Measuring 12 mm or 1/2" in diameter, these collimation knobs from Bob's Knobs fit Celestron 8" f/10 Schmidt-Cassegrain telescopes with Hyperstar and metric collimation screws.
  • Construction and threads both consist of black oxide steel.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • These collimation knobs are extra long compared to other metric knobs offered by Bob's Knobs in order to make up for the Hyperstar's countersunk factory screws.
$22.00

Bob's Knobs Celestron 8" SCT Collimation Knobs - Metric - Black Oxide - C8METBO

SKU: BOB-C8METBO
  • Measuring 12 mm or 1/2" in diameter, these Bob's Knobs Collimation Knobs fit Celestron 8" f/10 Schmidt-Cassegrain telescope models made in 2005 or later with Black Phillips factory collimation screws featuring metric threads.
  • Construction and threads both consist of black oxide steel.
  • Some telescopes may contain a small plastic cover over the factory collimation screw which will need to be removed before installing these Bob's Knobs collimation knobs.
  • These knobs are compatible with metric Fastar instruments only and therefore will not work with EdgeHD optics.
$22.00

Bob's Knobs Celestron 8" SCT Collimation Knobs Secondary - C8STD

SKU: BOB-C8STD
  • This Bob's Knobs Collimation Knob set fits Celestron 8" f/10 Schmidt-Cassegrain telescopes models manufactured after 1980 with factory silver, Allen, or Phillips collimation screws, either with Fastar secondary with silver collimation screws or without.
  • Each knob in this set measures 13 mm or 1/2" in diameter.
  • Made from black plastic with black anodized aluminum alloy threads.
  • Some telescopes may contain a small plastic cover over the factory collimation screw which will need to be removed before installing these Bob's Knobs collimation knobs.
  • These collimation knobs are not compatible with Celestron vintage orange optical tubes manufactured before 1980 as well as most telescopes with black Phillips factory collimation screws.
$21.00

Bob's Knobs Celestron 9.25" SCT Fastar Collimation Knobs Secondary - C925FST

SKU: BOB-C925FST
  • Measuring 9.5 mm or 3/8" in diameter, these Bob's Knobs collimation knobs fit Celestron 9.25" f/10 Schmidt-Cassegrain telescopes with "Trifid" Fastar secondary housing.
  • Made from black plastic with stainless steel threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • With these Bob's Knobs Collimation Knobs installed, it is crucial that the rotary secondary cover remain open.
$22.00

Bob's Knobs Celestron 9.25" SCT Secondary Collimation Knobs Metric - Black Oxide - C925METBO

SKU: BOB-C925METBO
  • Measuring 12 mm or 1/2" in diameter, these Bob's Knobs Collimation Knobs fit Celestron 9.25" f/10 CPC Schmidt-Cassegrain telescopes with metric screw threads.
  • Construction and threads both consist of black oxide steel.
  • The factory supplied dust cover will fit per usual with these collimation knobs installed.
  • Some telescopes may contain a small plastic cover over the factory collimation screw which will need to be removed before installing these Bob's Knobs collimation knobs.
  • These knobs are not compatible with CPC 925 telescopes with Trifid Fastar or EdgeHD optics.
$22.00

Bob's Knobs Celestron 9.25" SCT Collimation Knobs Standard Secondary - C925STD

SKU: BOB-C925STD
  • Measuring 16 mm or 5/8" in diameter, this Bob's Knobs collimation knob set fits Celestron 9.25" f/10 Schmidt-Cassegrain telescopes that have standard collimation screw threads.
  • Made from black plastic with black anodized aluminum alloy threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • Includes a set of long spacers so that the secondary housing lip can be cleared.
  • Prior to installation, please make sure the knob threads and factory screw threads match.
  • These collimation knobs are not compatible with the CPC 925 or telescopes with EdgeHD optics.
$22.00

Bob's Knobs SkyWatcher 5" - 10" & C6, C8, and C10; Newtonian Secondary Collimation Knobs - CNSEC30

SKU: BOB-CNSEC30
  • These Bob's Knobs Secondary Collimation Knobs fit a wide variety of telescopes including the Celestron C10-N/NGT, C8-N/NGT, Orion Astroview, Star Blast, Skywatcher, Skyview, SkyQuest XX and XT, and many more.
  • Each knob in this set measures 13 mm or 1/2" in diameter.
  • Made from black plastic with stainless steel threads.
  • Compatible with Celestron 6", 8", and 10" Newtonian reflectors as well, whether they contain GoTo electronics or not.
$22.00

Bob's Knobs Secondary Collimation Knobs for Orion OD Newtonians & C6, C8, and C10- CNSEC35

SKU: BOB-CNSEC35
  • These 35 mm long 4-Vane Phillips Secondary Collimation Knobs from Bob's Knobs fit a wide range of mass produced Newtonian reflector telescopes such as the Meade LightBridge and Astro-Tech Imaging Newtonian.
  • Each knob in this set measures 13 mm or 1/2" in diameter.
  • Made from black plastic with stainless steel threads.
  • Compatible with Celestron 6", 8", and 10" Newtonian reflectors as well, whether they contain GoTo electronics or not.
$22.00

Bob's Knobs Meade 10" SCT Collimation Knobs for 3-Screw Secondary - M10-3

SKU: BOB-M10-3
  • These Bob's Knobs Collimation Knobs fit Meade 10" Schmidt-Cassegrain telescopes such as the LX10, LX50, LX90, LX100, and LX200 models.
  • Compatible with Meade telescopes featuring 3-screw secondary mirror holders only.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • Comes with an Allen wrench for factor collimation screw removal.
$18.00

Bob's Knobs Meade 10" SCT Collimation Knobs for 6-Screw Secondary - M10-6

SKU: BOB-M10-6
  • Measuring 16 mm in diameter, these collimation knobs from Bob's Knobs fit Meade 10" f/10 Schmidt-Cassegrain telescope models with 6-screw secondary housing like the LX200, LX200R, LX200ACF, and LX90.
  • Made from black plastic with black anodized aluminum alloy threads.
  • Comes with an Allen wrench for factor collimation screw removal.
  • Meade 10" SCT models introduced prior to 2005 have 3 screws and therefore require different collimation knobs.
$18.00

Bob's Knobs Meade 10" SCT f/6.3 Collimation Knobs w/ Dust Cover Spacers - M10WF

SKU: BOB-M10WF
  • These Bob's Knobs Collimation Knobs fit Meade 10" Schmidt-Cassegrain telescope models including the LX10, LX50, LX100, LX200, and 2120 models with f/6.3 Wide Field marked on the corrector ring.
  • Each knob in this set measures 19 mm in diameter and features stainless steel construction.
  • Comes with an Allen wrench for factor collimation screw removal.
  • A set of spacers to be attached to the inside of your telescope's factory dust cover is also provided to ensure that the dust cover fits properly.
$27.00

Bob's Knobs Meade 12" SCT Collimation Knobs For 3 or 4 Screw Secondary - M12-3

SKU: BOB-M12-3
  • These Bob's Knobs Collimation Knobs fit Meade 12" f/10 Schmidt-Cassegrain telescope models featuring secondary housing with 3 or 4 screws such as the LX200.
  • Each knob in this set measures 16 mm or 5/8" in diameter.
  • Made of black plastic with black anodized aluminum alloy threads.
  • Comes with an Allen wrench for factor collimation screw removal.
$18.00

Bob's Knobs Meade 14" SCT Collimation Knobs For 6-Screw Secondary - M14-6E

SKU: BOB-M14-6E
  • Measuring 16 mm or 5/8" in diameter, this set of Bob's Knobs collimation knobs are designed for Meade 14" f/10 Schmidt-Cassegrain telescopes with 6-screw secondary housing and exposed factory collimation screws.
  • Made of black plastic with black anodized aluminum alloy threads.
  • The factory supplied dust cover will fit as per usual with these collimation knobs installed.
  • Comes with an Allen wrench for factor collimation screw removal.
$18.00

Bob’s Knobs understands that telescope collimation can be a struggle for observers new to astronomy, but it is crucial to enjoying your telescope to the fullest. Optics out of alignment, or collimation, yield images with noticeable imperfections. For example, stars will not come to a pinpoint focus and planets will look slightly hazy. The best way to prevent this from happening is to collimate your scope.


To achieve collimation, telescopes often include screws which require a screwdriver to modify the position of the mirrors. Unless you are careful, that screwdriver could scratch your optical tube assembly, or even the optics themselves. Moreover, your OTA’s mirrors are highly sensitive, and it can often be difficult to get such a precise micro-adjustment with a screwdriver.


Collimation is often the most frustrating aspect for beginners, but it doesn’t have to be. Bob’s Knobs makes it easy to collimate your Newtonian or Catadioptric telescope with their collimation thumbscrew sets. There’s no screwdriver, no Allen wrench. Simply install the knobs and you are ready to collimate with the twist of a wrist. Bob’s Knobs work with many Catadioptric and Newtonian telescopes, from makers like Celestron, Meade, Orion, and more! Not sure where to start? The experts at High Point Scientific are ready to help you get the most out of your scope!

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