Best viewed at "original" image size.

The two images above illustrate the difference in noise with temperature. The image on the left
is a 5 minute exposure at ISO 800 at 22 deg. C. The image on the right is a 5 minute exposure at
ISO 800 at - 4 deg. C. The left image was contrast stretched to bring out the noise details and
the image on the right was processed with the exact same parameters. As you can see the image on
the right has very little random noise and you are left with the noise inherent in the sensor and
electronics.