🚀 go-pugleaf

The single exposure is actually better, because it has a single read-out noise component, whereas the 300 one-minute ones will have 300 read-out noise components.

Not quite right. It depends on how you use the multiple exposures. If you combine them in a summing device, the s/n ratio goes up as a function of the number of images being summed. It is a log function, not a square root function in that case.

Of course, the closer you come to the exposure threshold, the lower the s/n until the noise swamps the signal.

CCDs have inherent noise characteristics that makes them the better candidate for sensors than CMOS. But CMOS is far cheaper to manufacture, as CMOS is so ubiquitous in silicon production, and it's cheaper to deal with the noise using software.

A Peltier cooler is indicated if the chip is indeed heating up to the degree you indicate, Ramon. In any case, thermal noise is only one of the sources for sensor noise.

Fred, the only films that can even come close to today's sensors is Tech Pan and Kodachrome, With K a distant second to Tech Pan.

IMO, of course. :-)
 Nice shot of Andromeda Galaxy, Ramon.