November 26, 2014
Juniper And Stars, Coyote Buttes Wilderness, Vermilion Cliffs National Monument, Arizona

I've always been intrigued by star trail images, but had never tried it until two nights ago. Conditions were perfect with a sliver of moon setting an hour and a half after sunset and a forecast for clear skies overnight. I set up at an area that would have an interesting composition looking north, and I'm quite happy with the result. :)

Here are the (boring) technical aspects. When I set up shortly after sunset, I first made a series of images that would be appropriate for the landscape part of the image. I only used one of those exposures, the darkest, and processed it three times: one for the foreground and tree as exposed, one for the sandstone cones adjusted for one stop less exposure, and one for the sky adjusted for two stops less exposure. Then I set up the Canon Timer Remote Controller TC-80N3 to wait for 1.5 hours, then take a series of 12 minutes exposures with 10 seconds in between. It got down to about 20°F (-6°C) over night, and the camera battery only lasted for 14 exposures or 168 minutes. I processed the star images with high contrast and in B&W to get the most star images with no odd colors. Then I combined the three landscape images to get a natural-looking scene, and put the star images on top in "lighten" mode so that the star trails from each of the images would stick out over the dark sky. Voila — an interesting image.