|
Depends on several factors.
1. Sensor temperature, the lower, the longer max. exposure.
2. ISO value. Most optimal ISO is the highest with an acceptable dynamic range, which is 800 for many lower end DSLRs but 1600 for DSLRs like EOS 6, 5, Nikon FX bodies and Nikon D500 or Sony A7.
3. Tracking accuracy / polar alignment. For me, I get decent images without guiding when I just set BQ Octantis (not Sigma !) in the center of the polar scope field, 600mm FOV (full frame) and 4 minutes per frame.
4. A rough guideline is that the real exposure value of a stacked inage is sqrt(number of frames) * exposure per frame. So 10 frames of 1 minutes is NOT equivalent as a single 10 minute exposure, but just a single 3.16 minute exposure with one third of the noise. Noise is also inversely equivalent to number of frames, compared to single frame of that exposure.
5. Most important: avoid light polluted areas, unless you use decent filters like UHC or Halpha. But Rockhampton is not that bad I think.
|