It looks like some kind of diffraction artifact to me. Try defocusing about 5mm on a field of bright stars or four images with the bright defocused star near each comer.
If you want me to look at it, PM the picture to me. I often don't return to posts once I respond because I just don't always remember too.
It looks like a diffraction artifact though.
It may very well have been. The scope is now on it's way back. I should have the replacement direct from Explore Scientific by Saturday.