Why Sonoran Desert National Monument
I captured these images in the Sonoran Desert National Monument about 30-40 miles southwest of Phoenix. The light pollution from Phoenix fades and the spiral arm of the Milky Way Galaxy can be seen.
I chose the Sonoran Desert National Monument because I have lived in the Sonoran Desert most of my life and had never visited before. It was a good compromise between dark skies and drive time; drive took me an hour and a half each way.
Creating the Still Image
This composite image is the result of 114 still frames (30s f/2.8 ISO100) stacked using the lighten blend mode. This blend mode allows the brighter pixels of one image to show through to the layers above. It achieves the same effect as leaving the cameras shutter for the entire duration of the sequence. Except better, because the final image contains less noise and can be editing in additional ways, such as a timelapse sequence.
Creating the Timelapse Video
The video I edited also makes use of the lighten blend mode, in this case utilized in Adobe After Effects. As layers are sequentially made visible, the brighter parts remain visible, creating the illusion of the stars trailing across the sky.
I could also edit this video so the images use the “Normal” blend mode. This is basically just flipping through the images successively. Then the Milky Way and all the stars in the sky would move as single points across the sky. It’s a cool perspective too, but I like dramatic mood offered by the trailing effect.
Future Plans for The Sonoran Desert Startrails Elements
One more idea I’d like to play around with would involve using After Effects expressions to code an animation effect. The goal being to turn several images within the stack on then off in sequence to create more interesting movement. For example, 20 image long streaks with 40 image long gaps, so the trails look like lights on a marquee.