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Alpine observatory provides a peak experience

Mike Long

A long-exposure photo shows star trails whirling around one of the antennas at IRAM's observatory in the French Alps. The stars turn around the celestial north pole during the course of the night. For more of photographer Mike Long's work, check out his website.

Stars whirl above one of the antennas of the Plateau de Bure interferometer in the southern French Alps, which is operated by the Institut de Radioastronomie Millimetrique, or IRAM. This otherworldly view of one of the world's highest millimeter-wave observatories was captured by photographer Mike Long, who passed along a jaw-dropping view of an Alpine supermoon earlier this week.

"I hiked up the mountain with the sole intention of creating an image of star trails around one of the six arrays on the plateau, and was fortunate to learn from staff members working there that one of those arrays would not be moving that particular night," Long wrote in an email. "The image is a composite of 24 five-minute exposures, and any movement would have resulted in a very blurred satellite dish, essentially ruining my efforts."

Long explained that it takes multiple exposures to capture the full swirl of star trails on a digital camera, because a single, two-hour exposure would burn out the camera's sensor. "This was a lot easier back in the film days," Long said. The separate photos are stacked together after they're taken, using software that lines up the star trails.

IRAM's astronomers, engineers and other staff members live on the mountain throughout the year, at an elevation of 8,365 feet (2,550 meters). In 1999, tragedy struck when a cable car carrying 20 IRAM employees to work disengaged and took a 250-foot plunge. All of the riders were killed.

"Hiking up the trail to Plateau de Bure, there are several memorial plaques at the scene of the accident," Long wrote. "A sober place indeed."

More about millimeter-wave astronomy:

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.