[5ash (Philip)]

I appreciate why darks are taken to remove thermal noise and hot pixells and that they must be taken at the same temperature as the lights. This is best achieved with short exposures where the lights and darks can be taken within a short time interval . However when taking long exposures over several hours the darks will be taken at often very different ambient temperatures whether taken before or after the lights. This does not take into account the heating of the sensor over that period. My question is " for long exposures using a standard uncooled dSLR would it not be better to use the noise reduction routine available in the camera "? I know this doubles the time for each exposure but it would overcome problem of temperature changes over a photographic session of many hours.

Regards philip
PS any recommendations on a 2" light pollution filter for dSLR astrophotography