do not centre

Confirmed. I will need to be mindful of NCP in the Celestron finder scope with the barn door tracker.

The specs of the finder are 6 x 30 with a 7° field as inscribed on the device.

So I'll need a chart, or software, or an app, to accurately show it. And I will need to eye-ball the relative distance from centre. Bearing in mind that the cross-hairs are off a little.

As well, I need to figure out a way to ensure the scope itself is parallel to the hinge.

I'm pretty sure I'm seeing trailing arcs in last night's 3 minute images...