I've just noticed an issue with my new Askar FRA300 OTA which I'm diagnosing and some input from others here would be handy. I have contacted the vendor with my report but whilst I am waiting for a response it would be good to see if there is anything that I may have missed or should look at.
The Askar FRA300 is paired with a ZWO ASI6200 MM Pro and 2" filter wheel with Astronomik 50mm filters. I have installed a ZWO EAF for auto focusing and the ZWO M68 OAG for guiding. SGP Pro is used for image acquisition and auto focus.
The issue is that I am getting what appears to be collimation errors in the blue channel only. See attached images which are a 200% zoom of the field. Stars in the centre of the field are fine. The aberrations in the blue channel start to become noticeable about 2/3 of the way across the field and become progressively worse towards the edge of the field and in the corners. No such aberrations appear in the red or green channels.
Here is a link to a Dropbox folder with a sample of each of the red, green and blue subs if you want to have a closer look.
I have not encountered these sorts of issues previously in one colour channel only. Any experience that others can bring to the fore would be appreciated.
Thanks,
Rodney