Monday, March 05, 2007

False color for H-alpha shots

People asked about how to make color from monochromatic image of the sun. Here're the steps which I usually do:-

1. Adust the level of the whole picture as you would do in any picture, astronomical or not, solar or not, to maximize the usage of the whole dynamic range

2. Adjust the level, this time only blue channel. Push it all the way to the right, around 90% to 95% depending on your preference

3. Adjust the level, this time only the green channel, observe the histogram, push it to the point where it peaks

4. Adjust the level, finally, only the red channel, only minor tweak is required to get good color, again up to your own preference.

That's about it. You might also want to adjust the curve a little bit to bring out some more subtle detail, especially when you're shooting with a non-double stacked system.

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