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| Re: Nightscapes using AstroTrac Tracking Mount |
Contrary to what I thought intuitive, most astrophotographers using dslrs recommend the ISO sweet spot of 800 instead of something like 100. I haven't researched it heavily to give a scientific explanation.
Shooting at 800 or 1600 is preferred over 100 for several reasons. First of all, the higher ISO means a shorter exposure time which allows for more shots in a given session. Secondly, stacking images improves the S/N ratio as hot and variable pixels are removed. Shooting multiple darks also gives a reference for subtraction of high ISO noise. Finally, shorter exposures also reduces tracking errors. I'm sure there are other reasons I've missed so please chime in. Dave
Can someone help me with what understanding what shooting multiple darks is? I've seen reference to it a lot but not an explanation. Is it shooting some images in the same framing at a shutter speed and exposure that results in completely black images that are used in post processing to reduce ISO noise?