Strange Flats, do I have an issue with filters or Image train ?

[teoria_del_big_bang]

Having just fitted a new FW and camera (QHY268M & QHY FW3) to my Esprit 100ED my first attempts at flats look a bit odd.
An unstretched flat looks reasonable.

But when auto-stretched left is new setup and right is with my old setup (ASI1600 & SX FW but same 36mm filters) stretched to same degree

The original setup looks much more centralised to me whist the new setUp the centre of the image looks to be towards the bottom of the image.

Using CCD Inspector, again new setup on left.

 

So do I have a problem and how do i overcome it ?

Steve
 

Edited March 2, 2021 by teoria_del_big_bang

[teoria_del_big_bang]

Does anyone know how to centralise this ?
Or is it really not a big issue ?

I assume there is something to adjust on the focusser but what ?

I would be grateful if somebody has ad the same issue and managed to centralise this on a Esprit.

Steve

[tomato]

I presume your FW and camera are in a screwed together arrangement on the focuser and so therefore must be reasonably centralised in the optical train?

If so, is there perhaps some  tilt/misalignment with your flats illumination source?

 

[teoria_del_big_bang]

Yes everything is bolted together apart from the last spacer that screws to the flattener.
I can;t really feel any slop in the focusser that is causing tilt and not sure I personally can see evidence of any n the few images I have take,, but not too experienced with tilt and how to cure i.

Steve

[teoria_del_big_bang]

Here.s a few stacked Ha images, I can't really see any evidence of tilt, but again not too sure what I am looking for, I assume elongated or shaped  stars on one part of image.

Steve