Quote:
Originally Posted by Peter Ward
Ah..this old chestnut. 
Let's say you have a noiseless 95% QE camera ( I wish )......then one might be tempted to say you could stack hundreds of 2 second exposures and expect to get a great result.
Sadly the physical reality is the photons are simply not raining down fast enough for that to work well with very dim objects/structures. Shot noise will dominate the image.
Guess I'll have to go back to my "old school" KAF16803 sensor... chilled to 65C below ambient... and calibrate out the noise...a good deal of which is from cosmic rays. 
Anyway...the point is to explore what your gear can do and to have fun in the process  |
Thanks Peter. That has cleared that up in my head to some degree. I guess it comes down to being "lucky" enough to have the sensor collecting particular photons at that particular time. Add to that the download time and the dithering delay, you are missing a few photons there I guess. Having longer exposures increases the likelihood of collecting those elusive photons and getting the signal above the noise. But on that train of thought, similar to the whole monkey randomly typing the complete works of Shakespeare, if you have enough short exposures you will get a decent result - EVENTUALLY... But, how long will that take!?
once again, thanks Peter, that has helped