On Monday, August 21, 2017, the Great American Eclipse occurred. This was a total solar eclipse (within the path of totality) and a partial eclipse for the rest of North America (including me). This wasn’t the first total eclipse in my lifetime; I remember a partial eclipse as a Michigan grade schooler in 1979. My class made special pinpoint eclipse viewers out of old boxes and tin foil. But I’m much older now, and I can make something snazzier. So I designed a DIY Eclipse Viewer Tube pattern that can be lengthened for a larger image of the eclipse! The next total solar eclipse in North America will be in 2024.
How do eclipse pinhole projector/viewers work? The idea is that a tiny pinhole in the foil at one end (which is aimed at the sun) allows in enough sunlight to project an inverted image of the eclipse on the other end of the tube. This is also known as a pinhole camera, or camera obscura. It works well!
Most people make their pinhole projectors out of old cardboard boxes, or even cereal boxes, which limits how big the projected image of the eclipse can be. But with my design, you can make yours as long as you wish for a larger, better image. You can estimate how big your image of the eclipse will be by multiplying the length of the tube by .01 — for example, a six-foot-long tube will project an image .072 inches in diameter (roughly ¾ inch).
This viewer is SAFE because it is an indirect view of the solar eclipse, and this is the safest way to view it (other than watching a video inside, of course). If you make this for children, I recommend you keep its length short — it’ll be easier for little hands to hold and aim, and their young eyes can see the smaller image of a short tube easier anyway.
So a longer tube will give you a bigger image. But keep in mind that it will also dim the light a bit more. The shorter the tube, the brighter the image. I made the tube in this tutorial about 60″ long. But I also made another one just one-foot-long so I could compare the images. Pick the size that works for you, or make several!
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DIY Eclipse Viewer Tube Materials
- 12″ x 12″ cardstock in a dark, non-reflective color (you’ll want one sheet for each 11″ of tube you wish to build)
- 8.5″ x 11″ white paper or cardstock
- Tape (both Scotch tape and Duct tape)
- Small piece of uncrumpled aluminum foil (you an also use a dark piece of thick paper instead)
- Push pin or needle (optional, used only if you don’t cut your aluminum foil out with the Cricut)
- A way to cut out your pieces (I use a Cricut, but you can also use scissors)
- My free pattern/cut files. (These are available in my resource library — get the password to it by filling out the form at the bottom of this post)
DIY Eclipse Viewer Tube Step-by-Step Tutorial
First, cut out your cardstock using my pattern/cut files (in my free resource library—get the password to it at the bottom of this post). If you’re using scissors, use my PDF pattern to print and cut out your cardstock. If you are using a Cricut, upload the SVG file to Cricut Design Space and insert them onto your canvas. Ungroup ALL layers. The rectangle section without the cut-out window can be duplicated as many times as you wish to extend the length of your tube (I put three of them into the file by default). You’ll also need to change the two score layers to Score. Then select the black layers and the score layers and click Attach before you cut out anything, or the score lines won’t be in the correct place. Note that the gray circle is for your aluminum foil — just tear a piece off your roll and put in on your Cricut mat. It cuts beautifully on the same cardstock setting you use for everything else in this project.
Once your cardstock pieces are cut out, it’s time to assemble the viewing tube. Start by rolling a rectangle WITHOUT the cut-out window lengthwise around another cylindrical object, such as the aluminum foil tube, a vinyl roll, a tennis ball tube, or anything else cylindrical like this. Rolling it around a cylinder helps it bend without creasing.
Now tuck in three tabs into the three slots and tape down the edge well.
Roll another rectangular section (extender tube) lengthwise. Before you tape down the edges of the extender tube, insert it into the first tube so it overlaps the end without the window by one inch. Tape down and secure the two tubes together with tape.
Add as many extender tubes as you wish, making sure they overlap the previous one by an inch and are well secured.
Once you have your viewing tube the length you want it to be, it’s time to add the window for the sunlight. Tape the circle of aluminum foil carefully over the sunburst window of the circular piece with tabs.
If you cut out your aluminum foil using the Cricut, the pinhole was already cut for you. If not, use your push pin or needle to poke a clean hole in the center of the aluminum foil.
Fold up the tabs on the circular piece with the aluminum foil and insert it onto the end of your tube. Tape it down securely. Hold it up to the light and look inside — do you see any holes? If so, cover them with extra bits of cardstock and tape.
Roll up the rectangle with the viewing window on one end and attach it to the other end of your viewing tube. Make sure the viewing window is at the END of the tube.
Now tape your white circle into the center of the other circular piece with tabs, then fold up the tabs. This is your projection screen.
Insert the project screen cap into the end of your viewing tube. Rather than tape it down, however, you should be able to wedge it into the end where it will stay. (I will explain why I prefer not to tape it in the tips below.)
Duct tape all the joints while the tube is lying on a flat surface, like a table, to keep your tube straight and strengthen it. Your eclipse viewing tube is now ready to use!
Hold your viewing tube up to a VERY STRONG light (sunlight is best), with the aluminum foil window aimed at the light, and angle it so you can see a pinpoint of light projected onto the white circle. If it works, you’re all set to use your viewing tube for the eclipse!
To use your eclipse viewing tube, point the pinhole end of the tube directly at the sun. To aim your tube, move it around until you see a round spot of light on the paper at the opposite end of your tube—that light is the projected image of the sun! Trouble aiming your viewer? Find your box’s shadow on the ground, then move it until the shadow is as small as possible (it should look like a perfect circle). Be sure you do not look through the pinhole at the sun! Look only at the projected image on the white paper. Once you have it in position, rest it on your shoulder (if the angle works for that).
Eclipse Viewing Tips
If you want a larger projection, remove the projection screen section you wedged into the bottom of your viewing tube and place a sheet of white paper on the ground. Hold your tube up, aimed at the sun and pointing down at the paper. You will see the eclipse projected onto the paper on the ground even larger than in your tube!
Remember, never view the sun with the naked eye or with optical devices such as binoculars or telescopes. Use only certified eclipse viewing glasses. I tried to make a tutorial on how to make these, but the special solar filter plastic that you needed to make these was already sold out!
Find out how much of the eclipse you’ll see from your location with this calculator. I will see an 80% eclipse here in Ann Arbor, which is pretty good!
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Enjoy the eclipse! And if you make a viewing tube, please share your photo. Email them to me at [email protected] and we’ll share them here.
This is my favorite image from Miriam Giles — her husband was impressed with the viewer! He says, “Thank you! It worked really well.”
Here are more photos from readers who made and used my DIY eclipse viewer with great results!