Quote:
Originally Posted by PRejto
I find my LP is in quite a gradient and certainly not smooth over the whole image. How would you process the RGB stacked frames to eliminate the gradient? I've taken note of the requirement to do this before stretching (but without stretching I find it somewhat difficult to see the gradient). My usual tools are CCDStack and CS-5. I've had some success using the flatten background tool in CCDStack before creating the RGB combine in CCDStack. However, I don't always have success with that tool.
|
Honestly, my knowledge of the latest versions of PS is really quite limited, but I'm assuming you can 'layer' a stretch on top of a linear image layer. I imagine you should be able to 'sandwich' your model subtraction in between, so that you can see what you're doing, even though all the data is still linear - the 'stretch' that is layered on top will help you see. When you're ready to finalise the light pollution-less image, you simply remove the stretch from the layer stack and flatten the image.
I've heard FITSWork (free) has a gradient removal/modeling tool that you could try. And GradientXTerminator is a Photoshop plug-in (paid) for this very purpose.
In the meantime, if you've gathered the data and would like a hand with the modeling, let me know. I'm pretty keen to try this technique myself with some data - one of my users reported success with technique when I suggested it, so I'm pretty keen to replicate it!