How to Make a Pinhole Viewer for the Total Solar Eclipse, and What to Do While You Wait for Totality
Solar eclipses take time. What you will see in the middle of the event will vary enormously depending on where you are located, but from every vantage point in the U.S. the moon will slowly cross the sun for about 80 minutes.
That's a lot of time to wait. If you're standing within the path of totality, you'll then get to see a totally eclipsed sun and a spine chilling view of the solar corona for 2+ minutes. But everyone will then have another 80 minutes to watch the moon move away from the sun. So what to do with all that time?
1. Catch the sun.
Looking at a partially eclipsed sun through solar eclipse glasses is fun, but you're divorced from your surroundings. A much better way to share the eclipse experience is by projecting the crescent Sun onto a flat surface for viewing. Everyone can then view the spectacle with their backs to the Sun, which is the safest way for kids (and more social for everyone). Here's how to make a pinhole viewer from a tube and even a cereal box; use as long a mail tube as you can find, carve a 2-inch by 2-inch viewing square about 1 inch from one end, put aluminum foil over the other end, and in it center make the smallest pinhole you can.
With your back to the Sun, aim the foil end at the eclipsed Sun and look through the viewing square; the sun's disc is projected onto the inside of the bottom of the tube.
2. Project the sun through binoculars.
If you've got a pair of binoculars, this is an even simpler way of sharing the spectacle. All you need is two sheets of cardboard. Trace around the lenses of the binoculars on one of the sheets of cardboard, cut out the holes, and fit the cardboard over the binoculars. Now take ONE of the lens caps off. When you aim the binoculars at the sun, the cardboard creates a big shadowed area on the floor. Put the other sheet of cardboard on the floor and you'll get a surprisingly big, magnified image of the crescent sun.
It works best if you have the binoculars on a tripod. You can do the same thing with a telescope (or go one better and build a sun funnel).
3. Bring your kitchen gadgets.
A partial eclipse is bit like making pasta. Slotted spoons, sieves and colanders may be associated with draining spaghetti, but they’re also perfect for watching a partial eclipse. Anything with well-defined small holes will work as a simple pinhole projector. As the sun slowly thins to a crescent, hold the spoon or colander in between the sun and some white card (you'll have to hold it pretty close) to create tiny crescent suns.
If you happen to have a 3D printer at home, you can download a simple pinhole projector from NASA. A much cheaper alternative is to stand under a leafy tree and look for lots of crescent suns projected onto the ground through pinhole-sized gaps in the foliage.
4. Observe confused animals.
There are lots of anecdotes about how animals react to the darkness of totality: Birds stop singing, horses trot back to their stable, and flowers begin to close. But do they? Really? Looking for hard evidence is California Academy of Sciences in San Francisco, whose Life Responds is looking for citizen scientists to make observations on the iNaturalist app.
“The project was inspired by a trip I took to the 2012 eclipse in Australia,” said Elise Ricard, public programs presenter supervisor at the California Academy of Sciences. “I noticed that birds had stopped singing, and that it had got really quiet – I thought that was absolutely fascinating and I wanted to figure out a way to use citizen science to document it at a future eclipse.”
The Life Responds team will put together a list of target plants and animals ahead of the big day, and it's simple to join in. “We're asking people to take at least two, and preferably three, photographs of plants and animals at least 30 minutes prior to totality – or greatest partial eclipse, depending on where you are – one within five minutes, and another 30 minutes after,” she said.
5. Capture the sounds of silence.
Videos of eclipses are usually static, and actually pretty boring. You kinda had to be there. But it's the audio track that tends to be a keeper. Although the celestial spectacle itself is a completely silent event, the way people react to seeing totality is anything but. People often initially whoop, cheer and clap, but as totality takes over for a couple of minutes, a weirdly respectful, awed silence descends.
Put your phone on to record audio and you might capture someone – perhaps even yourself – whispering, swearing, or even weeping. That's exactly what the Eclipse Soundscapes Project is after. It's aiming to capture people’s reactions for sociologists and psychologists to study, but data on the soundscapes of wider natural environments as they change during totality will also be studied. Audio from before, during and after totality will also give the blind and visually impaired an opportunity to experience the event.