[cventer]

At the AAIC it was suggested via numerical evidence that Pixinsight does the best job of aligning/stacking images keeping the tightest stars.

I thought I would test it for myself.

I aligned and stacked 8 identical frames across 2 sets of images. 1 set was binned Red filter data. The other Full Frame Red Filter Data.

I only own CCD Stack and downloaded a trial copy of Pixinsight last night.

The results are not conclusive at all and suggest their is very little in it if anything. In fact I like the look when zoomed in of the stars CCDStack produced for the binned 2x2 images much better. The non binned I could not visually tell the difference.

I have attached a screenshot of the results.

But summary is:

2x2 Bin
Pixinsight defualt setting: 0.87px
Pixinsight lanczos3 setting: 0.87px
CCDStack lanczos36 setting: 0.89px
CCDStack Nearest neighbor setting: 1px
CCDStack Bicibic B-Bspline setting: 1.5px
reference image: 0.98px

1x1 Binned Data
CCDStack lanczos36 : 2.69px
Pixinsight lanczos3 setting: 2.73px
reference image: 2.07px

The difference is probably within the handling of floating point data within each package and not enough to worry about.

What it shows though is defualt setting for Pixinsight seems to be lanczos. Defualt in CCDstack is nearest neighbour so this is why some may report this difference in FWHM values when aligning and registering.

I cannot get a conclusive view on implementation of lanczos. Some say it does a very mild deconvolution.

Interested in thoughts and results from others and other packages.