A History of the Sky captures 360 24-hour time-lapses of the sky over the course of a year. Ken Murphy, a self-described "programmer, artist, and tinkerer," custom-designed the technology to shoot 8,640 photographs a day from the roof of the Exploratorium, a science museum in San Francisco. The setup includes an old point-and-shoot digital camera, a computer running Ubuntu Linux, a 4GB memory card and a network connection to automatically transfer the photographs, which totaled over 3 million in the course of the year. He shares how he did it in an interview below.
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The Atlantic: What inspired you to get into time-lapse photography?
Ken Murphy: I had the idea for A History of the Sky before I'd played around with time-lapse at all. The original concept was to create a visualization that used real patterns from nature in an abstract and hopefully interesting way. Time-lapse photography wasn't a part of the plan at first, but once I started experimenting with it, I knew I wanted to incorporate it into the piece. I find the technique compelling because it tunes us into events that unfold at a rate that we're otherwise unable to experience directly.
The camera setup, with a Canon A520 with wide-angle lens.
Why did you choose the roof of the Exploratorium as the place to shoot A History of the Sky?
Finding the right spot for a long-term time-lapse project is tricky. I needed a location that was secure, where I could leave my shooting rig undisturbed for a long period of time, and had power and network access. Furthermore I wanted a clear view of the northern sky, so that the sun or moon would never be in frame. After poking around on Google Maps, I realized that the Exploratorium building was the perfect spot; it's at the northern edge of the city, with an unobstructed view over the Bay and Marin headlands, so there is minimal light pollution at night. Fortunately I'd worked with some people at the Exploratorium before, so I approached them with the idea, and they said yes.
The camera setup looking north over San Francisco Bay and the Marin headlands.
What is the time-lapse interval of photographs in A History of the Sky?
The camera took a picture every 10 seconds, around the clock. That's 8,640 images per day, and over 3 million per year. I chose that interval because with anything less than that, the movements of clouds and fog would zip by too quickly when I played them back at 24 frames per second.
How did you put all the images together to make the video?
As the images were captured, they were automatically downloaded, renamed according to the date and time, and saved to a big external disk. I then used a variety of open-source tools with a bit of my own programming to process the images into the large mosaic video.
Is there anything you want to shoot a time-lapse of that you haven't tried yet? What's next for you?
Lots of things! I'm starting to experiment with time-lapse studies of tidal movements of bodies of water, and have begun collaborating with the Exploratorium again for this project. I feel like there's a lot more to explore with the panoramic technique also – playing with different spans of time as well as different subjects. It works well in an urban setting and with groups of people, as well as with more expansive natural scenes. I plan to do some traveling in the near future around California and beyond to shoot some more panoramic pieces.
All images courtesy of Ken Murphy. For more work by Ken Murphy, visit http://www.murphlab.com/.
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