I've taken a break from narrow band one-shot-color imaging here in Austin for some broad band full color images under bright city skies. With light pollution we can still record every photon from our distant target. Light pollution gradients can be subtracted from the image, however this leaves behind a shot noise component. In a broadband image this noice componet can be reduced simply by taking more data, reducing noise with the square root of imaging time. Here are two examples of M31, the Andromeda Galaxy. The latest below was the result of 20 hours integration time with a wideband Baader Skyglow with UV/IR cut filter.

Austin City Lights Andromeda Galaxy

The image below was taken under dark skies at Bad Wolf Ranch. Processing and equipment were almost the same. A similar quality of result was obtained with 4.25 hours of exposure.

Bad Wolf Ranch Andromeda Galaxy