Bob's Knobs iOptron 8'' RC Secondary Collimation Knobs

Bob's Knobs iOptron 8" RC Secondary Collimation Knobs

£25.00✓ 2 year warranty


5x in stock shipped 1-2 working days

About this product

Model:  bk_at8rc_sec
Part Number:  AT8RC

Replacement collimation knobs for iOptron / Astro-Tech / GSO / Orion / TPO 8" RC Series telescopes.

Bob's Knobs are the BEST option for tool-free collimation.

Simple to fit and easy to use.

Collimate your telescope without an Allen key or screwdriver!

Instructions are supplied but can also be found online as well as useful FAQ.

Images are representative and may not show the exact knob size / threads.

IMPORTANT: Please ensure the Bob's knobs threads and factory screw threads match before installation.

Knobs for iOptron / Astro-Tech / GSO / Orion / TPO 8" f/9 Ritchey-Crétien Secondary

Part: AT8RC
Fits: Astro-Tech, GPO, Orion (US), and TPO 8" f/8 RCT secondary (solid or truss-tube)

Knobs: Black plastic, 16 mm (5/8”) diameter
Threads: Stainless Steel.
  1. Two sets of knobs, each with a different screw length, are included with your order. Use the length that fits your telescope best. There should be one or two screw thread turns above the secondary housing. In most cases the dust cover will fit without contacting the knobs.
  2. If the dust cover cannot be installed because of knob height, you can use a shower cap in its place.

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