Quote:
Originally Posted by Peter Ward
Wouldn't many of the one minute exposures have no signal at all? Hence you collecting noise rather than signal.
Also, if the camera is downloading, that lone photon might be missed entirely....as opposed to the camera with its shutter being open most of the time.
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1) Many of the exposures would indeed record no photon, only background sky. However, since the SNR increases with the number of subs, the statistics quickly discerns between noise and faint signal
2) Given the random nature of photon arrival, over the course of the 10 minutes the window of opportunity to miss the photon is longer with many shorter subs but over the course of the hour it is improbable (although not impossible) that the photon arrives while the camera is downloading on each occasion, and thus the stack still records a statistically significant photon