I observe a strange star deformation I have no explanation for. The star deformation I know already is coma, star deformation caused by differential flexure or star deformation by field curvature.
Correct me if I am wrong but coma or star deformation due to field curvature seems to be circular centric around the middle of the frame, so you see the star deformation only in the corners.
Differential flexure affects all stars in the frame.
So now here comes my problem: I only see star deformation along the diagonal, so from upper left corner over the middle to the lower right corner. Upper right and lower left is okay.
Upper left, lower right with deformation:
Center with deformation:
upper right and lower left WITHOUT deformation:
This pattern appeared after changing from Ha to OIII Filter in my filter wheel. I could see it in the last frames of Ha maybe also a little, but it came up much more present in the OIII images.
The first images I took in Ha were absolutely flawless, circular sharp stars over the whole frame.
So the whole problem has a time aspect and also the shift to OIII made it much more present...
I used a ESPRIT100, 0.79 flatner (TSRED379), ASI1600MM, imaging train is screwed together, filterwheel is a starlightXpress 5x2"Filterwheel, Filters used: Baader Planetarium 7nmHa, 8.5nm OIII. Mount: EQ6R, Guidescope: 60/240 with ASI290MINI
Havent seen anything like that, do you experienced folks know what might cause that?
Any advice is highly appreciated.
Edited by CvBadengoth, 21 March 2019 - 04:38 AM.