bambi851 Unfortunately there is a big tree behind my house exactly where polaris sits, so I was looking forward to trying the ASIair alignment.
You do not need to see Polaris -- FWIW, Polaris is not even at the North Celestial pole, and not used for Polar Alignemnt because of that.
Does the tree create an obstruction more than about 30º away from the pole ? I.e., can you at times see the star Caph, or the Heart Nebula, or Kochab?
If you can see those stars at certain times of the night, you can use the pole-base Polar Aignment by placing the starting declination to something other than 90º.
The equations will work out, althought you will get less precision because of a secant of an angle close to 0.
Take a look at:
https://bbs.astronomy-imaging-camera.com/d/11580-polar-alignment-without-polaris/11
https://bbs.astronomy-imaging-camera.com/d/11643-asiair-polar-alignment-without-visibility-of-the-pole
https://www.cloudynights.com/topic/666852-rainbowastro-rst-135-review-the-ideal-imaging-mount/?p=10253290
In your case, replace the horizontal roof obstruction by the vertical tree obstruction and start the mount at an hour angle not at Meridian, but at some angle on the side of the tree. You also do not need visibility of the sky while the polar alignment process is moving that 60 degrees, You just need for the frame to be clear (to plate solve) at the start and at the end of 60º slew.
Just draw out your horizon carefully and you should be able to find the devlination angle and hour angles that will work. 30º a a large distance in the sky.
Chen
