If you acquire your data with a achromat refractor, your data may be suffering from the purple halo effect (chromatic aberration). There is a very quick and easy way in StarTools to get rid of the purple/bluehish fringes, from where you can further reduce any halos using the 'Magic' module.
You can go from this;
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- megrez_m42.jpg (98.62 KiB) Viewed 11848 times
To this;
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- megrez_m42_fringekiller.jpg (96.36 KiB) Viewed 11848 times
To attack the purple fringes, simply launch the 'Filter' module;
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- img2_004.jpeg (102.94 KiB) Viewed 11849 times
Click Mask, and create a star mask that is suitable. You'll want to include anything that is very bright and/or over exposed, i.e. anything that can cause the chromatic aberration to be prevalent;
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- img2_005.jpeg (171.04 KiB) Viewed 11849 times
Next, back in the 'Filter' module, set 'Filter Mode' to 'Fringe Killer' and 'Filter Width' to '1' (the latter lower value makes the filter more responsive to colours that are close - but not exactly the same - to the ones you click). All you have to do now is zoom into a star that exhibits the chromatic aberration and click on the offending halo.
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- img2_006.jpeg (70.14 KiB) Viewed 11831 times
After clicking a few times, this is the result;
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- img2_007.jpeg (69.48 KiB) Viewed 11849 times
