How to avoid Star Trails with the '500 Rule'

I only recently discovered the work and talent of David Kingham! 

How to avoid Star Trails with the '500 Rule'

"Due to the rotation of the earth it appears as though the stars are moving through the sky in long exposures. Star trails can be a desired effect when done for much longer exposures like this imageStarry Night which was a 90 minute exposure. But in this case we want points of light to represent how we see the stars with our eyes. To achieve points of light you can use a simple rule, it's often called the '500 rule'.

500 Rule: 500 divided by the focal length of your lens = the longest exposure before stars start to trail or blur (in seconds).

Read the entire article here

© 2011-2013 David Kingham

This work by David Kingham is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

http://www.davidkinghamphotography.com/night