ASIAIR Pro will. Ot plate solve

fcjr

I am using an Explore scientific 102 CF f/7 scope...714 focal length with a ZWO 294 MC. I have input those numbers. Under PREVIEW and PLATE SOLVE, I get the same message...”plate solve failed”. “ Maybe not enough stars or clouds.” “Check focal length.” But there are stars visible and there are no clouds out and I checked the focal length and it is correct. Why won't it plate solve?

w7ay

A couple of things to check:

1) make sure focus is tack sharp,

2) if you are using a reducer or flattener, make sure you account for how its changes the focal length,

3) make sure there are no shadows of buildings or trees branches protruding into the frame (minor protrusions are often OK when the sky is very dark)

4) stay at least 30 degrees away from the poles.

5) try setting focal length to "0" and let ASIAIR figure it out for you.

A wrong back focus when using a reducer can also throw off the focal length value.

It is best not to give it a specific focal length the first time you try to plate solve. Set the focal length to 0 (yes, zero) and let the plate solver figure it out for you. A zero value will take a little longer to solve, since ASIAIR is doing a more extensive search. Once it succeeds, it will place the proper focal length into the focal length field.

Chen

fcjr

Thank you! My focus was way off. Dumb of me. It now plate solves almost instantly!

w7ay

You are very welcome.

If you are using a reducer and the focal length is not the expected value, you may want to check the back focus distance. An easy way to check back focus error is to look at the stars in the corners of a star field of a large sensor (the error is small when the sensor is much smaller than the designed image circle of the reducer).

If the stars looks like streaks which radiate from the center of the frame, the back focus (distance from reducer to sensor) is too short. If the streaks are circular arcs around the center, the back focus is too long. If the four corners have different star shapes (circular on some corners, radial on the others), you may have a tilt where the sensor is not orthogonal to the optical axis, and if the streaks are not symmetrical to the center of the frame, the center of your sensor could be offset from the optical axis.

With a little care, you can get round stars from corner to corner.

If there are streaks even in the center of the frame, then the problem is tracking, and not optics, ha ha.

Chen