System Gain and Read Noise for Atik 460ex?

[mcgillca]

Hi - I have been trying to understand the noise in my system, so tried to determine the system gain and read noise for my Atik 460ex.

The system gain comes from plotting the mean signal vs the variance for a series of flats with a range of brightness values and I get 0.165.

The read noise from variation around the mean bias frame and I get 3.24 electrons.

The read noise is great, and well below the stated spec of 5, but I was a bit surpised by the system gain - this would translate into a full well of about 11000 electrons - I was expecting closer to 20000.

I haven't measured the dark current (the camera is at a remote observatory, so hard to do). Does the system gain seem right?

Colin