How to make a pinhole projector

Seth Jarvis

The annular eclipse is fast approaching. In preparation of the May 20, 2012 event make your own pinhole projection box.

You’ll need:

Materials for a pinhole projector

- a long box (at least 4 feet long, you can tape two small boxes together)

- a pair of scissors

- a thumbtack

- a box cutter

- tape

- a piece of white paper

- a small square of aluminum foil

One of the simplest ways to view the eclipse is to create a pinhole projector, which is a fancy term used to describe a long box with a pinhole in one end.  Sunlight shines through the pinhole and an image of the Sun is projected to the far end of the box.

There are three essential ingredients that go into a good pinhole projector:

1)      A long box.  The longer the better.  The size of the image of the Sun that the box projects is only going to be about 1/100ththe length of the box.  That means that for a box that is five feet long the projected image of the Sun is only going to be a little over a half-inch in diameter. If you can’t lay your hands on a single long box, consider taping together two or more smaller boxes.

Step 1 - Measure a 1"x1" square at one end of the box.

 

Step 2 & 3 - Cut out the hole and then cut a piece of foil large enough to cover it.

2)      The hole through which the sunlight passes needs to be very small, very thin and very round.  Aluminum foil makes an excellent pinhole surface; it’s thin, opaque to light, and a pushpin or thumbtack makes a near-perfect round hole in it.  For our pinhole projectors, we like to start with a square hole about one inch across in the cardboard of the box, then cover the hole with a small sheet of aluminum foil.  You can then carefully punch a hole in the center of the aluminum foil with a needle.

Steps 4 & 5 - Cover the hole with the foil and tape it. Then, punch a small hole with a thumb tack in the middle of the square of foil.

3)      Use a sheet of white paper as the projection surface opposite the pinhole. The Sun and eclipse will be much easier to see on white paper than if you just try to see it on the brown cardboard of the box.

Step 7 - Tape a square of white paper to the opposite end of the box (inside it.)

We recommend you try your box out well in advance of the eclipse.  Aim your box so that the pinhole is pointed at the Sun and the image of the Sun projects onto the white paper at the opposite end of the box. If your box is projecting a nice round image of the Sun with fairly crisp edges, then you’re ready for the eclipse.

Step 8 - Go outside and try it out. Point the end with the hole toward the Sun. You can see here there is a small dot of light on the paper. That's the light from the Sun!

 

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29 thoughts on “How to make a pinhole projector

  1. Pingback: VisionHealth EyeCare » Blog Archive » Annular Solar Eclipse May 20, 2012

  2. I am so excited to view the eclipse with my family, I was 13 the last time and it will be fun to share the experience with my kids. We will be making this project for safe viewing, thanks :)

  3. Hold a pair of binoculars with the big end pointed toward the Sun. You only need one barrel of the binocs for this, you can leave the lens cover on the other unused barrel.

    The binocular will then project an image of the Sun out of the eyepiece. Tape a piece of white copy paper onto a large piece of cardboard and use it as a projection surface for the image coming out the back of the binocular. Experiment with distance from the eyepiece to hold the paper. A foot or two distance between the binoc eyepiece and the projection surface seems to work best for me. Experiment for yourself.

    You’ll see what I mean when you try it.

  4. Just made your pinhole projector and it shows the sun perfectly! It only took us about 5-10 minutes to make it. Now we just have to find more boxes for the other family members to make their own projectors. Thank you!

  5. That’s wonderful to hear.

    Btw, we’re discovering here that if you make your pinhole a skosh larger, say up to an eight of an inch in diameter, you get a brighter image of the Sun and it’s still crisp around the edges. Experiment!

  6. Pingback: Lots of Sunshine Sunday Until Moon Blocks It « Fort Worth News Feeds

  7. Thank you for these suggestions. We will pull out the binoculars tomorrow and try your excellent, cheap, and simple suggestion.

    I posted the binocular tip on my website and put links for people to come see your blog for the pinhole projector. I hope it brings more interested people!

  8. Thank You for your intelligents, I will share this with 5 children and their parents today. Happy Eclispe everone!

  9. Pingback: Solar eclipse: How to safely watch this evening’s ‘ring of fire’ | News Online

  10. In your picture you only have three sides of the box. Enclosing all four sides of the box, leaving only about 5 or 6 inches open for viewing at the bottom near the paper, also helps get a brighter image.

  11. You are correct, but it also limits the number of people who can see the projected image of the Sun. If you’re not going to share the pinhole projector with a lot of people, your suggestion makes good sense.

  12. This was so awesomely easy that even a Grandma could make it for her Grandson in just a few minutes. Thanks for the quick easy tips on how to view the eclipse!

  13. can you look at one of these through a camera’s lense and take picture of it?

  14. You can take a picture of the projected image inside the box – just don’t try to look directly at the Sun through any optics that don’t have filters made specifically for direct solar viewing.

  15. Pingback: Solar Eclipse « Our Children's Earth

  16. are you supposed to be able to see the sun? or just some light? i can’t tell if i am looking at the right thing.

  17. It should be a (right now) an image of the round Sun. If you made it correctly you’ll see the Moon begin to take a bite out of the Sun starting at 6:20.

  18. I heard today about making safe viewing “binoculars” out of x-ray film and toilet paper rolls…is this safe?

  19. dootilylootman poovyweenocrumpeto jony leeman tempytooo cwoopilotnout romper anne smith on said:

    oh this was the best thing i have ever tried!!! i can’t wait for the eclipse! and here’s an interesting fact, in denmark when there is an eclipes they give out presents because it is an exciting holiday. the pin hole projector works great. at the last solar eclipse, i was there and i used one of those. what could work better? but i was wondering about those glasses thingys. do they make it so you can look directly at the eclipse through them? and can you make them at your own home?

  20. SO PUMPED TO SEE THIS FOR THE FIRST TIME!!!!!!!!! I’m 16 so this is a big thing for me and I have a passion for Astronomy so this is almost an “astronomical” experience! :D

  21. I’m in Lucas,TX (near Dallas) what time roughly should it get here?

  22. If i don’t have any boxes but i have a cardboard cylinder 4 1/2 foot in length and 2 1/2 inches in diameter, will it work with that?

  23. We observed the eclipse by holding a piece of tinfoil with a pinhole in it up to a window then projecting it onto a white sheet of paper. I was amazed at how well it turned out.

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