Much appreciated Gaetano!
- I'm seeing some uneven lighting that does not seem to be corrected by your flats and does not seem celestial in origin (it undulates very fast). It could be too, however I'm seeing an over-corrected dust donut as well at ~ 5 o'clock. Any idea what might have causd this?
- I'm not sure if it's an ASTAP thing, but it appears over-exposed areas (e.g. star cores) exhibit values that are outside of the range specified in the FITS file. I think I have a slight bug in StarTools (i should clip the image properly), but I haven't seen this happen before. Will investigate.
- Your stars are affected by coma.
- It doesn't appear you dithered between frames - after flats it is your #1 way of improving your datasets!
Given your stars are affected by coma, the first thing I do is to correct the field with the Lens module. A side effect of this is that it warps diffraction spikes, however we'll be cropping out those stars anyway.
Because you did not dither, the Lens module will have caused some cool anti-aliasing effects in the background due to the pattern noise.
Pattern noise affects so many things and algorithms...
The background and gradients clean up reasonably well with the Vignetting preset. Defects remain, but don't forget the courtesy AutoDev in Wipe is configured specifically to make them visible to you - you can/should always stretch the image less to hide any remaining defects, especially if the object of interest is not image-filling (as is the case here).
So, the simple workflow is this;
--- Auto Develop
To see what we got (see above).
Parameter [Curvature Linked] set to [138.28 %]
Parameter [X1] set to [151 pixels]
Parameter [Y1] set to [604 pixels]
Parameter [X2] set to [1647 pixels (-1021)]
Parameter [Y2] set to [1601 pixels (-407)]
Image size is 1496 x 997
Parameter [Dark Anomaly Filter] set to [2 pixels]
Parameter [Aggressiveness] set to [96 %] (backing off a little)
--- Auto Develop
Parameter [Ignore Fine Detail <] set to [4.4 pixels] to make AutoDev ignore fine shot noise and pattern noise.
Parameter [Outside RoI Influence] set to [15 %]
Parameter [RoI X1] set to [659 pixels]
Parameter [RoI Y1] set to [415 pixels]
Parameter [RoI X2] set to [879 pixels (-617)]
Parameter [RoI Y2] set to [618 pixels (-379)]
Parameter [Detector Gamma] set to [1.00]
Parameter [Shadow Linearity] set to [49 %] Deconvolution
Auto-generated conservative mask
Parameter [Primary PSF] set to [Moffat Beta=4.765 (Trujillo)]
Parameter [Primary Radius] set to [1.9 pixels]
Parameter [Iterations] set to 
Parameter [Mask Fuzz] set to [22.5 pixels]
--- Wavelet De-Noise (switch Tracking off - chose Grain Removal)
Parameter [Grain Size] set to [6.0 pixels]
--- Wavelet De-Noise
Parameter [Smoothness] set to [71 %]
Hope this helps!