This past Sunday was an annular eclipse. As opposed to a total eclipse, an annular eclipse is where the moon is further away from the Earth, which means it doesn’t completely cover the sun. Instead you get a “ring of fire” effect. At least, we would have were we about a thousand miles further south, and a few hundred miles west of Kalamazoo. I had hoped that we would be able to see at least a partial eclipse, though. To that end, I started planning early last week.
The first major factor was the weather. Leading up to Sunday night it seemed like the western sky would stay clear until the maximum, which was supposed to be 7:54pm, Eastern. There was rain predicted for later that evening, but I had hoped that it would stay clear enough for us to see it.
The next major piece was how to see it. You can’t look at an eclipse directly with the naked eye – you need some eye protection like a welder’s mask, or a telescope with a sun-filter. Having neither, I opted to build a “pinhole projector” which would allow us to watch the sun and the the eclipse indirectly. The sun’s image would be projected onto a piece of paper/cardboard, which we could safely view.
Early on I decided that this would be a cool experience for Katherine – she had never seen an eclipse except in pictures, and I had been looking for science-y things to do with her. This definitely fit the bill. I pulled together some materials to build the projector the Thursday before the eclipse, but CJ stopped me. She urged me to let Katherine help with the construction. Like an idiot, I was just going to build the thing and let Katherine watch. The two of us building it together was a much better idea.
In fact, I went one step further, and video-tapped the two of us building it. Unfortunately, our video camera does, in fact, record onto tape. It has a USB connection that would normally allow me to digitize the video and post it for your viewing pleasure. I say “normally” because the last time I tried that I was a few years ago when I was running Windows XP. Now that every client machine in my house is running Windows 7, I can’t find compatible drivers for the camera. So, CJ and I are going to get the footage professionally digitized, and start looking for a digital video camera (yet another project). At any rate, I will post the video of us building the projector, testing it out, and then trying it during the eclipse as soon as I can.
We actually end up building two projectors – one was made out of a paper towel tube, and was meant as our prototype. The other was made out of a wrapping paper tube. The additional length means that the image projected onto the card at the end would be bigger. The prototype projector would only show an image about 2 mm across, while the full-sized one’s image was closer to a full centimeter.
Armed with our projector, we found a nicely open parking lot with a very clear view of the western sky. While the full-sized projector got a decent image during the mid-afternoon sun when we tested it (high in the sky, very bright), try as we might, we could not get anything to appear 6 hours later with the setting sun. The prototype projector, however, did have a faint image, but it was so small we couldn’t tell if there was anything in the way of a crescent shadow on it. Just about the the time when the eclipse was supposed to be at it’s peak, clouds started rolling in from the west, obscuring the sun. We decided to pack it up and head home.
I suspected that we might not be able to see any of the eclipse because Kalamazoo was so far out of the main line. I was mentally prepared for that. However, the projector failing was definitely a blow. Katherine was un-phased, though. She had a blast making the projector and trying it out, and wants to do more. That made the entire project worth it.
To that end, we’re going to the Kalamazoo Valley Museum on June 5 to watch the transit of Venus. It’s the last time in our lifetime that Venus will cross between Earth and the sun, and the museum is going to have telescopes set up to watch it.
Katherine and I can’t wait.