Dark and bias frames both help reduce noise but target different sources. Dark frames are taken with the same exposure length as your light frames and capture thermal noise caused by sensor heat during long exposures.
Bias frames, on the other hand, are ultra-short exposures that capture electronic readout noise inherent in your camera’s sensor every time it reads data.
Use dark frames to remove hot pixels and thermal noise, and bias frames to isolate the baseline readout noise. Together, they provide a comprehensive noise reduction strategy.
