The Pleiades star cluster. M45. September 7, 2021.

Thank you, Evgeny, for your question about the Hubble Space Telescope. You may be right, but how can this defect of the primary mirror being over-compressed be corrected in this optical system?

Remove the tube from the mount. Try gently moving the mirror; it should rotate freely in its clips but not be loose, to prevent collimation from shifting when repositioning the tube. If necessary, carefully adjust the tension.

Okay, thank you for your answer. I'll check the time. I understand that pinching of the primary mirror can occur due to temperature changes.

I think I understand you. You meant that the declination axis isn't tightened enough, which causes it to shift when the telescope is repositioned.

I see streaks from bright stars pointing in different directions in the photo—that shouldn't happen. The first thing that comes to mind is exactly over-tightening of the guide scope. The telescope isn't mine, so I can't check it myself.

Alright, I understand. I'll look into it.