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Apologies for a longish post...
Did a quick test to see if there were any measurable differences in using "regular" Master Dark (made from 28 subs of 900 s duration) and Master Bias (created from 200 subs) frames, as opposed to a noise-free Bias (created with PI SuperBias tool) and a near noise-free MasterDark (manually reduced noise).
I selected three different sections of a Ha image (900 s exposure), one containing low levels of signal (background), one containing some signal and one with high levels of signal and measured StDev for these three areas.
Then, after calibrating the same Ha image with MasterBias and calibrated MasterDark, I measured StDev for the same three areas in the new image. The process was repeated for the same sub "treated" with noise-free Bias and near noise-free Dark.
The differences, as expected, were miniscule...
Applying standard master calibration frames increased StDev in the measured area by 0.004% (background), 0.001% (some signal) and 0.03% (high signal) while applying SuperBias and calibrated noise-reduced Dark resulted in a decrease in StDev by 0.130% (background) and by 0.058% (some signal) and in an increase in StDev by 0.002% in high signal area.
Decrease in StDev for the two areas in the Ha image calibrated with noise-free Bias and calibrated near noise-free Dark could be explained by having a smaller mean ADU values. Since applying "regular" MasterBias and calibrated MasterDark also decreased mean ADU while sightly increasing StDev, I would suggest that the overall difference between the two techniques results in about 0.07% (rounding off averages for all three areas in both images) in favour of using noise free calibration frames.
Obviously further testing is required to provide with higher confidence estimates.
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