In my waning days in Badlands National Park, I did a 4 1/2 hour star trails time lapse, setting up my camera to take one photo every thirty seconds. In addition to wanting to create a time lapse video, I wanted to use some of the images to create a star trails photo by stacking the photos together. Unfortunately, I could not use all of the photos during the time lapse, as a storm came through the area. But, I was able to select 223 images captured over nearly two hours that were useful for creating a star trails photo.
Why use this method? Since it was a near-full moon, the light pollution in the sky was too great for a longterm exposure. Additionally, digital cameras simply cannot take ultra-long exposures due to noise. My one long attempt, a four-hour exposure, simply had too much noise in it to be useable. With this technique, a digital photographer could do a star trails photo covering four, five, six hours – the entire night if desired. The main issue then becomes power, which I have resolved by using a Powerbase battery in connection with an AC/DC Inverter to power my camera.
BLOG UPDATE: I have selected this image as my Print of the Month for June 2009. You can click here to purchase the print under my special rate for prints in that collection.