Star trails

This is an image I took with a long exposure. The exposure according to the exif was 2806 seconds (46 minutes 46 seconds). I was aiming for about 45 minutes (I went inside during the exposure as it was cold!). The shot was taken pointing almost due West starting at about 23:15.

The colours of the trails are the colours the stars appear to us and correspond to their surface temperatures (a very long time ago). The redder stars like the one on the far right are cooler stars, having surface temperatures of around 3,000-4,000C. White stars are at about 10,000C and white/blueish stars are about 40,000C or higher.

The only processing I have done with this is to adjust the brightness and contrast a bit. If I raise the brightness there is a lot of noise, but you can see more very feint trails.

I am not an astonomy buff and did not note which stars these are but it would be quite easy to point the camera at the polestar, or Ursa Major which most people know, and get some very nice trails.

This image was taken in our garden, and we do live in a country village, however there are street lights on the other side of the house, and about 500 metres away in the other direction is the A15, and beyond that a glow in the sky from Grantham which is about 20-ish miles away. I would think that if you went out to a really dark location, the results could be far better.

Definitely best viewed large!