chromatic aberration script or tips

[afigueroa]

Hi all

I am new trying PI it seems is very powerful and i have been very exited with the results until now.  I have been reading the forum and it seem i am the only guy taking photos with an acromatic refractor (f8.3 first scope) and i have been able to take nice photos of galaxies until know and my problem is after streaching always i have blue halos because of chromatic issue.  With Photoshop is very easy to reduce almost in 95% this issue with carboni scripts, i was wondering if you can give me any tip to do it something similar in PI.

Thanks and Regards
Antonio

[Carlos Milovic]

Hi Antonio

I have an achromat too
The first I would try is to deconvolve the RGB channels separately. Specially the blue one. Then, play a bit with the morphological filters to reduce the size of the stars. You'll need to build a good star mask, to avoid destroying deep sky data.

If all of this fails, another solution could be to create a mask with only the haloes (for example, take a look at the ColorRange process I developed, at the bottom of the forum board, in the CMSegmentation module). Then use SCNR or curves to decrease the blue.