Repairing Coma in star images

[This is just one of many articles in the author’s Astronomy Digest.]

No lenses are perfect and brighter stars near the corners of the image can show a form of coma making them look like little seagulls.   It is possible to make a brush tool which keeps the central part of the distorted star present, but overwrites the surrounding ‘wings’.

Makinga star repair brush tool in Adobe Photoshop:

If the coma brush is selected (with a double click so that the left and right square bracket ([ ]) keys can be used to control its size) one can copy from a blank region of the adjacent sky and paste over the star with an appropriate size.

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© Ian Morison