evilc Am I doing something wrong, or can Polaris not be so close to a mountain for this to work?
Yes. You can even polar align using ASIAIR with the pole 20ยบ or more below the horizon.
Do not point your telescope at the pole. With the ASIAIR polar alignment plate solve database, you can offset the declination angle at up to 30 degrees away from the pole.
Take a look at this thread (start at post #4 and diagram in post #11):
https://bbs.astronomy-imaging-camera.com/d/11580-polar-alignment-without-polaris/4
And this other thread, with a better diagram:
https://bbs.astronomy-imaging-camera.com/d/11643-asiair-polar-alignment-without-visibility-of-the-pole
When you increase the declination angle from the pole, the accuracy decreases. The second thread has a table of the accuracy that I measured back then.
As you have already noticed, the entire FOV of the scope has to be clear of obstructions to reliably plate solve. If the FOV includes shadows of trees, etc, ASIAIR will think there are lots of stars (at the edges of leaves, etc), resulting in false asterisms that will fail to plate solve.
When ASIAIR polar alignment rotates the mount's polar axis of the mount by 60 degrees ; it is trying to determine the center of rotation relative to a location on the sky. ASIAIR does not actually have to visually see that center -- it is just part of an equation.
Chen
