Quote:
Originally Posted by Rich_  How long must the exposure be before the rotation of the earth causes the stars to begin leaving a trail (assuming equipment to prevent this was not being used). All the stars in the original photo seem to be still points of light with no tails? |
I played around with some software for stacking images to make star trail photos a year ago. You take a series of 30 second exposures then merge them into one. Even the individual 30 second exposures showed slight smearing of the stars.
You can see some examples of the finished images in this thread:
Photographing star trails
Dave P.