Steven's Tree and Star Circle (19 exposures, 8 minutes each ISO 100 so a total of 2 hours and 32 minutes). First exposure was at 10:53 pm, the last at 1:18 am. Long exposure noise reduction OFF. f/4, 23mm.
NOTE: I have reprocessed this image and I like the (son of ) Bristlecone Pine Star Circle a bit better. See what you think.
If you're itching to do this kind of photography yourself, please visit Star Circle Academy.
To get this shot, I set up before sunset with a programmable timer (intervalometer) delayed 4.5 hours - so it started exposing at 10:53 PM. Moon set was at 11:55 so most of the exposures included moon glow - either direct illumination or skyglow.
After pressing the "start" button I drove back to Grandview Campground and went to sleep. These things are hard work :-) I got up at 3:00 am to go fetch the camera. It managed about 21 images before the battery gave out. I was hoping for about 4 hours worth. It was about 33 degrees Farenheit. The upside to the cold temperature is that it helped to keep the camera noise very low..
I used Digital Photo Professional (comes with the Canon DSLR cameras) to export 19 images as JPG files with little or no adjustments. I then used the excellent freeware program "startrails" by Achim Schaller to stack (combine) the images. This program takes the brightest pixel from each image and includes that pixel in the final image. Since the sky is very dark, the brightest spot on each shot is usually a star. Photoshop CS4 Extended has a "statistics" tool with "Maximum" that does something similar. Startrails.exe, however, is much easier and much faster than Photoshop for this purpose. Startrails also includes a "dark frame" feature to help set the black level and reduce noise.
After combining all of the images and producing a single TIFF file, I sharpened it and did some contrast improvements using Picasa3 - another free and quite powerful program. The primary enhancement was to increase the highlights and to slightly increase the shadows. This action alone brought out the color in the stars (and YES, stars do shine in red, yellow, orange, blue, and white). I'm sure I also adjusted the white balance slightly to "warm" the photo. My final action was to clone out the few odd bits of noise that remained. I used Picasa3's "retouch" feature for this.
This photo was taken during an outing of the Bay Area Photography and Exploration Society which I led. More details about my star trail photography technique are available via my Star Circle Academy BLOG or in my Short Treatise on Night Photography.
You may also find my timelapse treatment of this photo interesting and very short.
-- Copyright 2008, Steven Christenson
I reserve all rights of use for this (and all) my photography. Specifically copying, printing, reproduction, reuse or storing of this image are not permitted without my permission.
Featured in Explore #9 on 2008/10/08