About this product
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 SecondaryPart:
Astro-Tech, GPO, Orion (US), and TPO 8" f/8 RCT secondary (solid or truss-tube)Knobs:
Black plastic, 16 mm (5/8”) diameterThreads:
- 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.
- If the dust cover cannot be installed because of knob height, you can use a shower cap in its place.
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