ASIAIR PRO Trouble plate solving polar alignment

diomedes

Hi all, I used the Air for the first time tonight with my Celestron AVX, and Canon T6i. I focused with bathinov mask and pointed the mount roughly at Polaris. The air detected 34, 77, 124 stars but the plate solving always failed. When I did the preview I could see the stars populating the field of view. Any idea what could be going wrong? could I have been pointing way off from Polaris ? how much of a margin of error does the Air give you ?

IMG-6532 by Greg Borrelly, on Flickr

w7ay

diomedes Unless you are using a camera lens with 70mm focal length (or a zoom lens set to 70mm focal length), that "71mm" number does not look right.

Try entering zero (0) as the focal length in the Main Camera window, then perform a plate solve, and let ASIAIR figure out the true focal length for you.

Chen

diomedes

w7ay Hey Chen FL was correct. I was using a William Optics GT71 Refractor. I'm trying again tonight but I'm not sure what to do different to get a successful result.

diomedes

w7ay your 100% right, I swapped out my aperture for focal length !! big mistake. Thank you !!

w7ay

diomedes That is what I was afraid of.

The "71" of the William Optics GT71 is its aperture, not its focal length.

If you are not using a reducer, the focal length of the GT71 is around 420mm. If you use a reducer, the focal length will be reduced by the factor of the reducer, assuming your back-focus is precisly set.

It is best to let ASIAIR determine the focal length for you by setting to focal length to zero (yes, zero). The first plate solve will take a little longer, but once it plate solves and find the actual focal length, ASIAIR will use that number and subsequent plate solutions will be rapid.

Chen

diomedes

big hopes for tonight being successful ! I will set it to 0

w7ay

diomedes Very good chance it will work just fine. Good luck.

Chen

diomedes

today's forecast changed to clouds. I can't believe I made such a basic mistake 😅 I checked several times, but for some reason I entered the aperture number instead of FL. Anyway until the next clear night !

sebriviere

As focal lenght are not an exact science, stick 0 in there the 1st time, ASIAir will determine it.
You could end up with 418 or 422 depending on backfocus....

diomedes

Successful polar alignment today! My exciment however did not last long as I ran into issues with my mount not stopping while it slew or not responding at all.: