Dumbbell Nebula (M27)

My first experience shooting a deep space object through narrowband filters on a monochrome camera. The shooting was done at a sensor temperature of 0°C. The color was formed according to the HOO (bicolor) mapping, added on top of the luminance channel, which was shot through a UV/IR cut filter. Unfortunately, the OIII filter produces large halos around stars, so they had to be removed in this color channel.