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The collimation of an SCT can be a daunting task for a beginner, but it is an absolutely necessary process to get the most out of your telescope! Doing the collimation with the factory Phillips screws is certainly doable, but requires a lot of back and forth between the eyepiece and the secondary mirror. You also need to work, in the dark, close to the corrector plate with a sharp metal screwdriver, requiring a lot of concentration and precision in your movements.

By replacing the factory Phillips collimation screws of your Celestron 8 EdgeHD with a set of Bob's Knobs collimation thumbscrew, you can make the process of collimation an effortless and risk-free task. Simply grab a Bob's Knobs thumbscrew and turn!

Fits:Celestron 8" f/10 EdgeHD with Fastar secondary. Do not use on non-EdgeHD C8 telescopes. Be sure to check that the thread length on our knobs matches the thread length on the factory collimation screws.

Knobs: Available in black oxide steel* (black) or stainless steel (silver), 12 mm (1/2”) diameter.

Threads: Available in black oxide* or stainless steel.

*Black oxide steel is only adequate for dry environments. David Astro only offers stainless steel Bob's Knobs thumbscrews, as they are more suitable for Canadian weather. Stainless steel provides better corrosion protection in locations where dew is common.

Customer Reviews

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J
Jeremy

Works great!

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