Green haloes around stars
Posted 26 December 2012 - 09:49 AM
Here you can see an example.
It is a cut from a 70 min photo of the Lacerta contellation with Takumar 105mm at f/5.6. The green haloes are strongest in this image. In this illustration, I increased the green black point and overall brightness to make the haloes apparent. The original cut (2.4MB) can be downloaded here:
Please can you advise me, what are they caused by?
Posted 26 December 2012 - 10:45 AM
Posted 26 December 2012 - 10:54 AM
Posted 26 December 2012 - 11:09 AM
Posted 26 December 2012 - 02:03 PM
If it is one a whole roll, it could be a processing problem. You have a cross curve where the magenta layer, in this case, is developed to a higher (or lower contrast) to the other two layers. What results is highlights and shadows of complementary colors--if you have green highlights, you should see a magenta cast in the shadows.
BTW, both issue might not be significant under normal shooting condition, but the extreme contrast needed in processing astrophotography will accentuate them.
Posted 26 December 2012 - 05:37 PM
Posted 26 December 2012 - 05:55 PM
Posted 26 December 2012 - 07:58 PM
Posted 30 December 2012 - 02:27 PM