[pmrid (Peter)]

Until I caught the ASiair ZWO bug, I had been using SharpCap for PA and found it pretty darned good. Using a QHY PoleMaster CCD made it particularly easy.

The Polemaster is mounted on the RA axis of the mount - a HEQ5 or an EQ6. So it is aligning that axis. The underlying assumption is that your telescope is pointing to the same spot (cone error excepted).

Then, along came ASiair with it’s own PA routine. It uses your primary CCD and your imaging scope. If anything it is even easier than the SharpCap method but the same underlying assumption remains - is your scope correctly aligned to your mount’s RA axis.

When I first tried it last night, it told me that I was appreciably below altitude - to the extent of about 10 minutes. And also about 6 minutes off in azimuth. I had done a PoleMaster align a few days before and had not moved the mount in between.

Has anyone else had an opportunity to quantify the differences between the two approaches? When I get another clear night I plan to try to do so.