[Paul Haese]

This is a bit of a curiosity but I just wondered what the guys with PME's have to say about this issue.

Doing 20 minute subs has led to the discovery that I am getting some field rotation in the deepest parts of the corners on my images. 15 minutes subs are fine but most 20 minute subs show some slight degree of field rotation.

I am according to the Tpoint manual set for around the refracted pole and that is around +72" for my location for the ME.

So is it better to be at the pole? I would have thought so given I am getting some field rotation. I have been doing 20 minute subs for a while; long before I sorted the issues with the pointing, but the PA must have been better.

Thoughts? Recommendations if any.