Questions about astroimaging (or cosmoimaging?) with high end CCDs: Sony A7s or Mallincam Universe?

[D4N]

The thing with ISO is that above unity gain your not really adding any data and below it you are losing data. It doesn't make the sensor any more sensitive it just uses software to boost the signal and more software may be used to tackle the noise this typically generates. The same can be achieved in a more controlled way in post processing.

The annoying thing for me is that ISO refers to the film speed which really is a measure of sensitivity, unfortunately they used the same term for digital cameras and it has stuck.

Sent from my iPad using Tapatalk

[ollypenrice]

Low read noise changes the equation - big time.  The A7S has read noise below 1e at some high ISOs.  Compare that with the read noise of your Atik 11000.  You are absolutely right to keep to long exposures on astro-CCDs.  But it's no longer true for newer generation DSLR/Mirrorless cameras.

Mark

Yes, I'm watching the new sensors with a keen eye. When monochrome versions appear I think we'll all be in for a treat.

Olly

[Knight of Clear Skies]

This is the closest I've got to real-time astrophotography, a single 1-minute exposure on Andromeda with a bit of post processing to improve the colour balance and de-noise it somewhat:

This was taken with a 250mm zoom lens at f5.6, which isn't particularly fast and gives bad coma at the edges when wide open. Someday I'll try a quick trawl around the sky with a more suitable lens.

[dph1nm]

Remember the A7S has 8.3um pixels as well as extremely low read noise. That is very good news for imaging at long focal lengths.

NigelM