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Bob's Knobs C8 Metric Collimation Knobs

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Bob's Knobs C8 Metric Collimation Knobs

Now there is no more tools needed to make collimation adjustments to your telescope! It's easy . . . just grab a Bob's Knob and turn. You can even collimate while looking through the eyepiece on most telescopes. What's more, you'll never drop that pesky little Allen wrench or screwdriver in the grass again. Installation is a snap with included instructions, and you can undo the modification at any time.

The C8 Metric Collimation Knobs Fits: Celestron 8 inch (20 cm) f/10 SCT's made in 2005 and later years with black Phillips factory collimation screws (some CPC 800 models). These screws have metric threads. It is important that you choose the correct style Bob's Knobs for your telescope. Please note the number and type of screws on your secondary housing before ordering.

These knobs will fit only 2005 and later C8 models that have black Phillips factory collimation screws. All C8 models make prior to 2005 and all post-2005 models with silver factory collimation screws require C8 standard knobs. Check that our screw threads match the factory screw threads before installing.

Some telescope versions have a small plastic cover over the factory collimation screws. This cover must be removed and set aside when Bob's Knobs are installed. The cover is cosmetic only and will not affect operation of the scope. (Photo shows Bob's Knob's installed on a C8 with black Phillips collimation screws. Click our "Images" tab to see a picture of the screws without Bob's Knobs installed.)


ManufacturerBob's Knobs

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Brad Z.
United States

No tools needed to adjust now

These were simple to install and make the adjustment process painless and quick. No tools needed.

Scot W.
United States

Bob’s Knobs

Love the design, way better ,just make sure you have a commentator.