Mike n Trish, my initial reaction was to just 'let this go through to the keeper', but hidden in your thesis is the attitude we so often hear. While your theory is of course sound, the 'caveats' and 'all things being equal' are real gotcha's in many peoples lives, and i would add another one - budget. In a perfect world of a very dark site in an observatory with a good pier, a high end mount perfectly aligned and corrected, no wind, perfect seeing, etc etc your long sub ccd nirvana camera will out perform on SNR. However, many of us lack the financial ability ( through lack of funds or other priorities), to build the nirvana system. We have to deal with the short comings of our particular situations, and thus compromises are required in order to produce and enjoy imaging. What the new, low entry cost, very low noise, reasonable QE (say 60%) cmos cameras provide to us humble masses, is the ability to achieve more than we possibly could in the past with our obvious constraints.
