Quote:
Originally Posted by PRejto
Would that same ADU background limit value remain the same if a light pollution filter is used?
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Generally yes. However sometimes odd things happen with LP filters if the sky has a colour cast they are not designed to handle, blue moonlight for instance.
A case in point, I was trying to shoot the Orion nebula in moonlight with a CLS filter. After colour balancing, the image ended up noisy in spite of being "well" exposed, especially in the red channel. While the white light histogram showed good separation from the left edge, I discovered that when splitting the histogram into red, green and blue that the red channel was clipped. It had insufficient exposure. Double stacking a Baader semi-apo filter which reduced the blue channel helped get the red channel off the edge.
After that experience, I would suggest when using LP filters to keep an eye on each colour channel to make sure they get enough exposure.