Cumbrianwolf Posted March 2, 2022 Share Posted March 2, 2022 (edited) My feelings are that the scope cooled down a bit more than I expected after collimation and that the collimation went out? Or would I be barking up the wrong tree? Canon EOS 7D 254 mm F/4 1016 mm coma corrector and 30 second subs at ISO 400. Image below is not stacked and no editing. Edited March 2, 2022 by Cumbrianwolf Quote Link to comment Share on other sites More sharing options...
Cumbrianwolf Posted March 2, 2022 Author Share Posted March 2, 2022 I found the issue, during my cleaning of the primary mirror I failed to notice that the primary mirror clamps or at least two were quite loose, so the mirror could move ever so slightly and during collimation it was probably seated fine but vertically or horizontal it would have slipped and at F/ 3.5 with the corrector there is not much room for error! Now the primary has been recentred, and the secondary realigned by both laser and Cheshire collimating eyepiece, I have also thread locked the screws on the rubber mounts, so no more movement of the primary for a while at least. Quote Link to comment Share on other sites More sharing options...
Carastro Posted March 2, 2022 Share Posted March 2, 2022 Glad you found the cause of your problem. Carole 1 Quote Link to comment Share on other sites More sharing options...
Cumbrianwolf Posted March 2, 2022 Author Share Posted March 2, 2022 38 minutes ago, Carastro said: Glad you found the cause of your problem. Carole Thank you, I lost a lot of hours worth of data due to the issue, but in hindsight I should have kept an eye on what images coming back from the rig so that I could have intervened sooner. You live and learn. Quote Link to comment Share on other sites More sharing options...
GazAstro Posted March 4, 2022 Share Posted March 4, 2022 I had that on my SCT when the secondary screws were too tight. 1 Quote Link to comment Share on other sites More sharing options...
Cumbrianwolf Posted March 4, 2022 Author Share Posted March 4, 2022 (edited) 16 minutes ago, GazAstro said: I had that on my SCT when the secondary screws were too tight. It is easy to miss these things as you just do not think it will ever be an issue but these fine threaded screws do and will come loose, guess the constant expansion and contraction loosens them over time. Semi-permanent thread lock will now be used on all the fixture and fittings that should not move from now on. Not had the pleasure of a SCT, currently. Edited March 4, 2022 by Cumbrianwolf Quote Link to comment Share on other sites More sharing options...
Cumbrianwolf Posted March 5, 2022 Author Share Posted March 5, 2022 Well the problem was not the actual problem, I have some issues going on with this scope and a full strip and realignment is in order tomorrow as tonight was a wasted effort. Quote Link to comment Share on other sites More sharing options...
TerryMcK Posted March 5, 2022 Share Posted March 5, 2022 Hopefully you will get to the bottom of it tomorrow John. 1 Quote Link to comment Share on other sites More sharing options...
Cumbrianwolf Posted March 6, 2022 Author Share Posted March 6, 2022 Stripped it down, cleaned all mirrors and reassembled the OTA and of course fully collimated it with both the laser and the Cheshire eyepiece so that should rule that option out. Also checked the coma corrector for any flaws that could be present and cleaned that optical glass as well. The full kit and caboodle is now set up and ready in advance for tonight. Looking back on my other images that I first took, I can also see the triplet star deformations, so something is a miss. 1 Quote Link to comment Share on other sites More sharing options...
Cumbrianwolf Posted March 7, 2022 Author Share Posted March 7, 2022 Good news I have now sorted the issues and my images which I am working on have some superb data, there is a slight cast on the stars but only when you zoom in, and I think that was more of a tracking error. M42 is in the works with 90 minutes of exposure, let us see how my editing goes on this one. 1 Quote Link to comment Share on other sites More sharing options...
TerryMcK Posted March 7, 2022 Share Posted March 7, 2022 AP is all about problem solving and glad you have got it sorted now John 🙂 1 Quote Link to comment Share on other sites More sharing options...
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