4) registration,
we turn distortion correction on, the rest stays at default.
APP will report the results again in the file list:
1) the registration error in pixels is shown together with the amount of stars that were used in registering the frames to the chosen reference frame. The reference frame waschosen automatically after star analysis. And it chose the frame with the most stars combined with the star roundness and size as quality parameters. More stars are very important for the registration process, so it has a high weight in the calculation.
You’ll notice, that APP also reports star density and a relative FWHM measure of the stars in your frames. In this case they are identical since, your frames have all equal scale and image dimensions. If you were to combine frames of different scale and/or dimensions, the star density and relative FWHM will actually give a fair quality comparison between the frames.
So these quality parameters are reported independently for scale and Field Of View (FOV) between your frames. This enables APP to do a good quality assessment of your frames when you combine frames of different camera’s and/or telescopes.
