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My take is Well depth is still an important factor not to be ignored.
The choice of CCD for each person is very much dependent on so many things. : Budget, purpose (huge spectrum of requirements there - scientific vs artistic, planetary, Vs DSO, Vs photometric, blooming or antiblooming, spectral response and extended sensitivity at particular bands, binning capabilities, download speeds . . . ), the telescope being used and therefore image scale and all its considerations such as average local seeing conditions, degree of over sampling desired, well depth, dark noise, cooling, integrated guiding, filter wheels, adaptive optic capability, OAG options, light pollution etc etc etc
That is why there are books written on the subject and no one camera can ever suit all purposes or all people.
Thus its a personal thing because our needs are all a bit different.
Dynamic range is often a key factor in any decision (well depth e- / read noise e- or 20 * log(welldepth e- / readout noise e-) if you want it in db)
But Well Depth is one of the main things that allows us to image for a very long period of time to capture the very, very faint nebulosity without over saturating the rest of the image (ignoring stars).
Faint nebulosity has so few photons arriving that you either get a huge telescope or you expose for longer - since super high Qe is not generally affordable for mere mortals and true photon multiplying in silicon is likewise unavailable to us and really big telescopes are not quite so practical or affordable.
Exposing for longer is the cheapest, most affordable and available option !
So a long exposure with low well depth is harder to capture the full dynamic range of your target - (in one exposure) than a similar camera with greater well depth - despite having similar dynamic range.
After all, this is really the quest - to capture the enormous dynamic range of our chosen subject and compress it by so many orders of magnitude into an image that we look at (usually in an 8 bit format ! on screen or printed) and manipulate it to display the qualities we seek - dark dust clouds and shadows, enhanced colour, non linearly selectively stretched features etc to make it appealing and exaggerate these faint interesting and beautiful features
So to my mind there is some benefit to having a camera that has deeper wells than the Sony has (<>20,000e), irrespective of the chips dark noise or read noise and dynamic range calculation.
But they are making astro cameras more affordable and I think we are seeing the effects of this across the board.
Rally
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