Thursday, July 9, 2009

Star Trails from top of Mt. Josephine

The evening of July 4, Travis and I hiked to the top of Mt. Josephine to shoot fireworks and stay for sunrise the following morning. This gave me an opportunity to try a new method, for me, shooting star trails. After a couple of test exposures I set my shutter release to take a series of consecutive 5 minute exposures. The idea is to merge the resulting images together into a single image adding little by little to the trail of the stars with each succeeding image.

The last few evening I have been using a number of techniques to blend these images together. Some methods like Helicon Focus, OK don't laugh - you never know if it isn't going to work unless you try it and how many people have tried this, turned out to be a real disaster. I used a couple of methods in Photoshop using Lighten blending mode then another more involved method using Lighten and Screen blending mode. Each method left some artifacts that weren't pleasing to me.

Then last night I tried a little standalone program called Image Stacker. It's very simple, fast and quite inexpensive, $17, for what it does. I still need to play with it since some of the artifacts from the Photoshop method are present with Image Stacker. I need to make some prints to see if these artifacts show up in a print. I suspect in a smaller print they will not be noticeable but may show with something larger.

If you remember back to the 4th there was a nice moon in the eastern sky. These exposures were started at 1:42am so there was alot of light in the sky, not the best situation for star trails. This image consists of 17 5-minute exposures spanning 85 minutes. I'm looking forward to trying this process close to a new moon, with a dark sky, and let it run for hours.


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