Quote:
Originally Posted by rally
Couple of things worth throwing into the soup
I think there are two different routes - one for science purposes and the other for artistic and visual interpretation purposes.
Binning to gain an improvement in the SNR of the RGB channels especially for faint nebulae in the RGB colour channels and then non binning in the L channel for fine detail will give you "the cake and eat it too" !
The reason we appear to get something for nothing is the eye is very sensitive to luminous and contrast changes (more so than colour detail) - so the L channel will "trick" the eyes into seeing the enhanced colour detail in the RGB channels.
Something I have often wondered about is the actual size of the telescopes image circle, not just the useful spot size.
So whilst the focal length of the scope and the f ratio are known (and for higher end scopes so is the image circle) the image circle and its effect on light gathered at the CCD is often ignored.
I think its assumed that all light from the scopes aperture at the focus point is being harnessed - but is that the case for all scopes ?
ie is there light that is simply being focussed that is not on the CCD at all.
If that is the case ? (and I am asking the question rather than stating a fact) - is this not a factor that will affect efficiency ?
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Hi rally. good points.
the original post deals purely with broadband pixel-level sensitivity with the assumption that the designer will take care of how many pixels there are and what sampling is used based on other criteria - I guess that could have been made clearer.
However, you could define system efficiency in other ways and the fraction of total "controlled" photons actually put to good use might be one way of doing so - in which case total chip area would come into it. Have you seen any such definitions of sensitivity? - might be useful to compare. I guess that, with a small object like a galaxy, most of the image is a relatively uninteresting star field, but with a large nebula or glob, the field of view is possibly more important than pixel resolution. And for any sort of survey work, field of view is an essential part of the efficiency equation.