Make a Pinhole Projector for Eclipse Viewing

I'm a sucker for eclipses. Lunar, solar, full, partial. You name it. You just have to be armed and ready.

After all there's nothing better than a celestial event to get people to do things they don't normally do—stay up late, or go outside with anticipation. Or talk to complete strangers because they're sharing something extraordinary.

That's what it was like during the last solar eclipse I saw in 1992, in the middle of the workday. And of course, the advice then was the same as it is this week: Don't look at the sun.

We all came out of San Francisco City Hall, where I worked, with our little makeshift pinhole projectors. We all oohed and ahhhed. And we talked to each other. What are you using? Wow, that's better! Look at that!

When came out, I rejoiced. It's a rare event. You won't see one for years! You gotta go outside!

But I don't recall seeing an eclipse, ever, when I was a child. So with this one, I'm determined to make it a learning event. I told my 6-year-old that we're going to see an eclipse, something I never got to do.

Following the very simple do-it-yourself instructions, I decided to make a simple pinhole projector. There are variations on this. You can make it out of a long, narrow box. We went for no-fuss. It's the principle that matters here:

1. We cut up a recycled cookie box into two pieces.
2. We cut a square hole in it (why square? Who knows?)
3. We covered it with aluminum foil.
4. We poked a pin through the foil.
5. And then we took it outside for a test drive.

You can follow along with the pictures. We got all the materials from the stuff in our recycling bags. Your results may vary.

Have fun! That's the point.

What not to do is look at the sun with something that you heard will work, says Professor Andrew Fraknoi, chair of Foothill College's Astronomy Department:

"Sunglasses, exposed film, and smoked glass are NOT OK! If you have access to welder’s supplies (and not many people do), #14 arc-welder’s glass is an excellent filter (but it has to be #14 and not lower numbers). Or you can use special black or aluminized polymer filters/glasses available at many telescope stores or planetaria; make sure you get them from a reliable source."

And if that fails, or looks underwhelming compared to the hoopla over how cool the sun looks, See the list of Bay Area places that are hosting , like the one that Foothill College Astronomy Department chair . National Parks are getting into the fun of it. The Point Reyes National Seashore, which has event throughout the day, is listed among the parks that are "outside the annularity" but will have a good view.

Most of the events are run by astronomical societies and they know what they're doing. They'll have the right filters so that you can look right at the sun, safely.

I'll be at Foothill College observatory just to do that. With my pinhole project in hand—just for back up.