Fringe and halo killer

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Fringe and halo killer

Postby admin » Sat Dec 22, 2012 12:41 am

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;

megrez_m42.jpg
megrez_m42.jpg (98.62 KiB) Viewed 4303 times


To this;

megrez_m42_fringekiller.jpg
megrez_m42_fringekiller.jpg (96.36 KiB) Viewed 4303 times


To attack the purple fringes, simply launch the 'Filter' module;

img2_004.jpeg
img2_004.jpeg (102.94 KiB) Viewed 4304 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;

img2_005.jpeg
img2_005.jpeg (171.04 KiB) Viewed 4304 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.

img2_006.jpeg
img2_006.jpeg (70.14 KiB) Viewed 4286 times


After clicking a few times, this is the result;

img2_007.jpeg
img2_007.jpeg (69.48 KiB) Viewed 4304 times
Ivo Jager
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