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Snr
I did a brief experiment last night, after seeing some threads on CN lately where people are taking huge amounts (thousands) of very short (<= 4secs) subs and integrating them with seemingly good results; and I'm talking DSOs, not planetary. This had me questioning what I believed about SNR and image acquisition.
In the end, my brief experiment (no doubt flawed in many ways!) showed the conventional wisdom to be true: longer subs will give you better SNR, at least when you're "read noise limited".
All three of the attached images show a tiny crop of the edge of the Helix nebula. All images were calibrated. All images were stretched using PI's STF tool in combination with HT.
Where stacking was involved, Windsorized Sigma Clipping was used. Maybe not appropriate for the 5x1, but eh.
One is a single sub, 5mins in length.
One is 5 sub, 1min in length.
One is 57 subs, 1min in length.
Of the three images, one has a SNR of 4.8:1, another has a SNR of 5.5:1, the other has a SNR of 3.5:1
Can you guess which SNR belongs to which image?
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