Telescope-Collimation Tools-Bob’s Knobs Collimation Knobs for Skywatcher 190mm Mak-Newtonian Primary

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1. Scott T. Verified Buyer – 4 September 2023

   The primary mirror screws are too long but at least they fit. The secondary mirror screws are not long enough and the adjustment knobs are too big to both fit inside the secondary mirror well and thread in without cross threading. The Skywatcher MN190 secondary mirror well, where the adjustment screws are, is deeper than the length of the Bob’s Kn

   obs screws. The screws should be 3/8ths to 1/2 inch longer. The knob end diameter is too big to allow these too short screws to fit into the well, so you cannot thread the screw in when the knobs have to be inside the secondary screw well. I will be sending the secondary screws back for a refund. Also, I will probably end up Dremeling off some of the primary mirror screw length.