Quote:
Originally Posted by Astro_Bot
Physically, I loosened corrector cell retaining screws and lightly tapped the secondary holder to achieve movement.
After tightening the corrector cell screws, I took a final set of measurements to confirm no unintentional movement.
Of note, I found that the secondary holder did not measurably move relative to the corrector.
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You have to be very careful with the corrector retaining ring. It's touch only. No pressure. It's very easy to apply a lot of pressure with 8 screws or more over the circumference. It's like a flange. Only a small torque on each screw can add up to an incredible amount of pressure on the lens. Ideally the shims should be the only things stopping the corrector from moving sideways. If you apply too much pressure with the retaining ring you risk cracking the lens with thermal contraction/expansion if it's got nowhere to go.