We offer knobs for the Vixen R200SS Newtonian primary and secondary. Select the type of knobs for your telescope from the list below. Price is for a complete set of knobs.

A. Knobs for Vixen R200SS Primary

Part: R200pri
Fits: Vixen R200SS telescopes.

Primary collimation
  • Knobs: Black plastic, 13 mm (1/2”) diameter
  • Threads: Stainless steel
Primary Lock
  • Knobs: Red plastic, 16 mm (5/8”) diameter
  • Threads: Stainless steel
  1. Since the factory collimation and locking screws are close together, knobs must be staggered in height. The locking knobs protrude further than the collimation knobs. Locking knobs are now red for easy identification.
  2. Early versions of the R200SS primary use metric M5 screws for primary adjust instead of the M4 screws that we provide. You can pull a primary adjust screw, which is the Phillips screw, and measure the thread diameter. If you need M5 primary adjust screws with your knobs, please enter a note in the window provided during checkout.
  3. Protect the locking knobs from damage, and do not support the OTA using the locking knobs as feet.



B. Knobs for Vixen R200SS Secondary

Part: R200sec
Fits: Vixen R200SS Newtonian secondary.

Knobs: Black plastic, 16 mm (5/8”) diameter
Threads: Stainless steel

  1. The factory dust cover may interfere with Bob’s Knobs. A shower cap can be used as a substitute cover.