The video above is a time lapse of the annular solar eclipse that occurred in the western US on May 20. An annular eclipse, often called a “Ring of Fire” eclipse, occurs when the moon is far enough from the earth on its elliptical orbit that it does not completely cover the sun. As you can see, I was not far enough north for the moon to pass directly through the center of the sun, but it was still pretty dang cool. Literally. It got very cold at the height of the eclipse.
Your mama was right when she told you never to look directly at the sun. It’ll fry your retina as well as your camera’s sensor. So I had to build a camera obscura to view the eclipse. Actually, I had to build two: one for my eyes and one for my digital camera. The camera obscura works by using a tiny pinhole to focus light on a projection surface. The longer the distance between the pinhole and the surface, the larger the image, by a factor of about 100. So an 8’ long camera will create a 1” image. With this in mind, I went down to the art supply store and picked up a few poster mailing tubes, pieced them together with tripods of various sizes, and pretty soon had a rig that I could use to take my time lapse. The first photo below is one of my initial test shots looking down the tube, before I adjusted the exposure on my digital camera. The other two photos show the whole rig (taken after the fact). The second camera obscura (not pictured) was the same size but had a small eyepiece rather than the camera attachment shown here.
I walked over to Cesar Chavez Park, a big grassy park in the Berkeley Marina, to try out my creations. The rig for my digital camera worked great, but what I failed to account for with my handheld tube was the wind. The wind off of San Francisco Bay makes the Berkeley Marina an excellent spot for kite flying. In fact, the KiteMobile parks there on Saturdays and Sundays and fills the park with novice and enthusiast kite fliers. Unfortunately, that wind makes it a less ideal spot for trying to hold a 7’-long cardboard tube steady enough to view an eclipse. The tube was a great conversation starter though, and within a few minutes I had befriended a number of people who had all brought their own homemade eclipse viewers. We all passed our various contraptions around and took turns steadying the tube for each other. Stories were told and food was shared, and we all marveled at the eerie greenish hue that was cast over us, as well as just how freaking cold it gets when 90% of the sun is covered up.
Unfortunately, Jen had to work that day. I built her a paper-towel-roll-sized camera obscura to take with her, and she and some co-workers snuck out to view the eclipse as well. She got some great photos of the crazy crescent-shaped shadows that show up at the height of the eclipse. Once she publishes them, I’ll be posting them here.
There will be a total eclipse that passes through most of the US in 2017. Anyone who wants to join me for a viewing party is welcome. I’ll bring the camera obscura.