Tilt and curvature in my images

[ic_1101]

I'm trying to figure out why there is a curvature or tilt in my images as seem by the elongated stars in the top left of the image.

So far I have ruled out the sensor on the asi294mc pro as it's also present in my images taken with the qhy163m. I thought it might be the moonlite focuser but I checked the collimation with a Hotech laser and it's spot on. My imaging train is - SVR102T - sffr102t - spacers - asi294mc and all connections are threaded. The backfocus is exactly 55mm.
I'm at a loss to find the cause. Could it be a faulty reducer-flatner or the backfocus?
I ran CCD Inspector on the image and it shows the curvature and tilt. Any ideas please, I'm pulling out my hair in frustration.

[Ozypic]

I can't give you an answer I'm affraid ,but its still a great image. The nearer you come to perfection the more critical you will become . But not worth pulling out that hair ! I've noticed that lots of people have trouble with distortion in the outer edges and corners of their images. It is very interesting to see the tilt and curvature. I wonder if it would be different if you didnt tighten all your threaded conections as much. Or maybe you will just have to be content to crop the edges a bit . Good luck and thanks for posting it. Phill

[ic_1101]

Well I discovered the problem why I'm getting that apparent tilt in my images.
My imaging train was the svr102t - UV/IR filter - sffr102t ff/fr - spacers - asi294mc pro.
The issue was the positioning of the uv/ir filter. Being so far away from the sensor the slight refraction caused by the filter glass was amplified in the focal reducer/flattener and by the time it reached the sensor it resulted in the tilt. Really happy to get this fixed !!

[JayTee]

Amazing Alex, how the heck did you figure that out? It just seems like such an obscure detail.

Cheers,
JT

PS, CCDInspector, although a great program, does a really good job of creating more hair loss. jt

[ic_1101]

Thx JT, I think it was just dumb luck. After eliminating every other component I focused on the filter and it dawned on me that a glass filter will increase the light path to the sensor because of refraction. Since most filters are placed close to the sensor it's negligable but in my setup the filter is a ways from the camera plus the ff/fr being after the filter will amplify that defraction. Just in time cause I've pulled out most of my hair. Now to try and play with the backfocus to get a flatter field.