Collimation Knobs for Astro-Tech AT6RC & AT8RC Secondary

Bob's Knobs for Astro-Tech AT6RC & AT8RC Secondary Mirror Collimation Knobs simplify and expedite the collimation process by allowing tool-free changes, replacing the secondary mirror's conventional factory collimation screws. These sturdy black plastic knobs have a 16mm (5/8") diameter and feature premium stainless steel threads that resist rust and corrosion for long-term durability. Two different screw lengths are included to accommodate manufacturing variations in secondary mirror height, making them compatible with both the 6" f/9 and 8" f/8 Ritchey-Chrétien secondaries. Perfect for astrophotographers seeking effortless collimation adjustments even while observing at the eyepiece or wearing gloves.