Hi all,

Well I’ve returned to AP after a 2yr break and the first night didn’t go according to plan (what a shocker). I had a couple of issues (one I think I’ve just figured out). The other issue I’m having is with polar alignment. I used to get really good PA when I last did it and was eager to try the new version. I went through the process and got to the point of adjusting and this is where it all went wrong. I chose the Plate Solve Method and made my adjustments while looking at the updated error. Now two things confused me:

1) there is a triangle and a circle on the screen and my assumption is that the circle should be adjusted along the triangle until it rests on the apex. Yet when I made my adjustments the error was reducing but the circle was nowhere near the triangle. If I tried to adjust while on the triangle the error got worse.

2) If I let my mount settle and take a couple of exposures the error got worse! Even though I did nothing. How can this be?


I like the new PA routine but need some help in how to use it.

Rene

1. When you are using the plate solving polar alignment method, there is no real need to look at the triangles on the displayed image. It is just there to show your progress, but the main thing to do is to reduce the error numbers displayed by adjusting the altitude and azimuth knobs in the appropriate directions.

2. Sometimes the error value recorded is affected by the adjustment itself (e.g. when you turn those altitude or azimuth knobs, you're also rocking the mount a bit, and remember we're talking about very small angles), so trust more the second measurement after you make your adjustment and move away from the mount. That's my best guess as to what's happening.

Hy

Thank Hy. I managed to sort things out but was wondering if we leave tracking on during the PA routine or turn it off.

Rene

Tracking is on. Otherwise the images would have star trails.

Sorry for another dumb question but is tracking on during the Alt and Az adjustments?

Yes, tracking is on during the entire polar alignment procedure (except of course while the scope is slewing).
So, during the adjustment phase, yes the scope is tracking while errors are reported and when you are asked to make alt and az adjustments.
These tracking movements are accounted for when computing the adjusted polar alignment error.