Can someone explain the PHD2 calibration graph to me?

[Jay6879]

This isn't mine, but I'm curious as to what it all means. Should the lines ideally be 90° from each other on the cross hairs? What do the circles represent?

 

[michael8554]

Yes, the RA and Dec lines should be at right angles, and the circles evenly spaced.

The circles indicate the distance between PHD2 Calibration Steps.

If the pixel size and focal length have been correctly entered, there should be about 12 circles.

PHD2 will then know how far an  X ms pulse moves your mount.

The bunched-up red dots at the origin shows there is Dec Backlash, which you should manually clear before Calibration.

There is a wealth of Help And How To guides available via the PHD2 Help menu, start with this:

https://openphdguiding.org/phd2-best-practices/

Michael