Knobs: Black plastic, 16 mm (5/8”) diameter Threads: Stainless steel
Notes:
Many Celestron 11” carbon fiber tube and metal tube SCTs manufactured from 2000 to 2005 have the Trifid rotary cover Fastar secondarywith silver collimation screws that have standard threads, and require these knobs. See our hints for more information. Make sure the knob threads match the factory screw threads before installing the knobs.
The EdgeHD and some CPC 1100 models made in 2008 and later also have a Trifid Fastar secondary housing. These telescopes have black Phillips factory collimation screws and require metric knobs (below). 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
