[Cliff (Clifford)]

Hi astro744 , mental4astro, multiweb

Thank you for all your suggestions, I had an idea but having never really used a SCT before wasn't sure.

The spot seems very central so looks like Collimation is pretty good.

I hadn't thought about the Pupil dilation at night but that would have a large effect.

I certainly have light pollution , a Bortle 6 according to the Clear Skies App.

Cheers
Cliff