Knobs: Black-oxide steel, 12 mm (1/2”) diameter Threads: Black oxide steel
Notes:
These knobs will fit only the Celestron 8” SCT with Fastar secondary and EdgeHD optics.
These telescopes are marked “EDGEHD OPTICS” on the corrector ring. Do
not use these knobs on the non-EdgeHD Fastar secondary; the screws on
these knobs are too long. Be sure to check that the thread length on our
knobs matches the thread length on the factory collimation screws.
The factory dust cover will fit normally with Bob’s Knobs installed.
