Is this tilt?

[Phillyo]

Good morning all.

I'm using an ASI533 connected to my Samyang 135mm lens as shown below. Camera connects to the ZWO filter drawer which connects to the lens, all held in place with tube rings. However I've noticed in my images that the stars towards the edge of the frame aren't particularly round, especially one corner. The 533 only has a small sensor so I assumed the 135 lens would cover it with room to spare and yet I'm getting these strange star shapes. Can anyone confirm this is tilt? Anyone else with this lens have this issue? 

Oh, I also stop the lens down using stop down rings on the front element to around f/3.5ish I think.

Thanks for the help! 

Phil

[michael8554]

The ASI533 has a 1 inch diagonal sensor, which is plenty large enough to show tilt, which your image has.

There are posts featuring tilt on ZWO cameras.

What lens ?

I'd try another lens, or an OTA, before blaming the ZWO for sure.

Michael

[Phillyo]

19 minutes ago, michael8554 said:

The ASI533 has a 1 inch diagonal sensor, which is plenty large enough to show tilt, which your image has.

There are posts featuring tilt on ZWO cameras.

What lens ?

I'd try another lens, or an OTA, before blaming the ZWO for sure.

Michael

Unfortunately I don't have access to another lens/scope to test it on. I'll do a little bit of fettling and see if I can improve things at all. 

Thanks for the reply.