Alternative and Safe Ways to View Solar EclipsesPinhole Projectors and Enhanced Optical Viewing Devices
If you’ve already read our “How to view eclipses safely” post, you’re probably asking if there are even better ways to see the spectacle. Fear not, we have answers!
First, have you ever heard of a pinhole camera? What about a camera obscura? Well, they are inter-related terms, but a pinhole camera is exactly what you’d picture in your mind. And, fortunately, they are very easy to make.
Without going into the long explanation, a pinhole camera is simply when light enters through a very small hole or opening, like cardstock for example, and projects an image onto another screen. If you’ve been lucky enough, you may have stumbled upon a camera obscura in your room, like this person did and this one did. Here’s a good example of a camera obscura constructed in a room. Interestingly, the image that gets projected onto the other surface is upside down, but that’s no big deal. This is one of the best ways to safely view a solar eclipse. There’s absolutely no risk of visual harm. If you set one of these optical devices up, you’ll be able to look at an image of the solar eclipse all day.
So, let’s dive right into it. Here’s what you’ll need to make a cheap pinhole projector to view any solar eclipse.
First, get your materials:
- A box
- Box cutters or scissors
- A needle, tack, or something to punch a small hole with
- Aluminum foil or paper that is 100% opaque (i.e. not transparent). Whatever it is, it can’t allow light to shine through.
- (Optional) Glue
- (Optional) Foam poster board if you want to go the extra mile
Step 1: Get a cardboard box.
It doesn’t really matter how big the box is. It could be a shoebox. It could be a coffin. The point is that you need some apparatus that will close light out except for that small pinhole. If you wanted to go cheap, you actually don’t need a box. You could project the image from one screen (with the hole) to another second screen. We recommend a box because it will shut out light and make the image clearer. Just think about it, imagine seeing small speck of light on a screen. Would you rather see that enshrouded in the rest of the sun’s light? Or, would you like to see that up in the dark, like in a cinema for example?
So, once you’ve got your box, you need to decide where you want the pinhole to be placed and where you want to view the projected image from. You can’t stick your eyeball in the exact same place where you make the pinhole, right? Typically, you place your viewing hole on the side.
Pro-tip: Glue or tape a white piece of paper on the inside of the box where your eclipse image will project onto.
When you do so, make it as smooth as possible. Don’t let glue or unevenness in the box’s surface make the projection surface uneven. You want this surface as smooth as possible so that the projected image is clear. Bumps, ruffles, creases, chips in the surface will ruin the image.
Step 2: Cut a square hole where you’ve decided your pinhole side should be and affix a sheet of your opaque paper over the square hole.
You’re going to place a sheet of aluminum, cardstock, or whatever you ended up going with over that square hole you cut into your eclipse box.
Step 3: Cut another square hole where you’re viewing hole should be.
It doesn’t need to be too big. You don’t want too much ambient sunlight to enter the box. If you want to really amp it up, you can cut a circular hole and create a cylinder from cardstock to look through. This will help shut out more light. This resembling anything you’re familiar with?
Step 4: Then puncture your opaque sheet with the tack. Remember, this hole should be tiny–around 1-2 millimeters.
The key thing here is that the puncture should be clean, and it cannot be done through the cardboard of the box or through the foam poster board we mentioned earlier. If you use the cardboard or foam board you risk muddying up the image.
That’s it. You’re ready to rock your eclipse projection device and see the all the phases of the eclipse as the moon passes over the sun.
Not enough for you? Want more detail? The small pinprick of light too boring?
Well, let’s step it up. Go find the following items for me:
- A small refractor telescope or binoculars that you don’t mind ruining
- A tripod to mount either the telescope or binoculars.
- Two poster boards
- Boxcutters or scissors
- (Optional) Tape
- (Optional) A 2nd tripod If you have a second tripod to mount a piece of posterboard, even better!)
First, let me be clear, you are to never, ever look into the viewfinder/eyepiece of the telescope or the binoculars while it’s pointed at the sun (unless you know what you’re doing and have a solar filter over the scope or binocs). This go back to our safety post earlier. You will go blind. So remember this rule and tell to everyone around you when you’ve set this up.
Also, the tripod should be mandatory. You could hold the telescope or your binoculars with your hand, but that’s tiring and creates a difficult viewing experience for others.
Step 1: Take your poster board and affix to over the eyepiece of your telescope or binoculars so that it is blocks sunlight from passing onto your other screen.
Ideally, you’ll want to cut a hole in this first piece of posterboard so that you can just shimmy it over the eyepiece(s). The idea is to block ambient sunlight from washing out the second piece of posterboard where the eclipse’s image will project onto. We’re making the projected image clearer by making it darker in that area.
Step 2: Aim the telescope or binoculars towards the sun.
Keep in mind, unless you have a solar filter, this may ruin the optics in your telescopic device. The sun packs a lot of energy!
The way to check if the telescope or the binoculars are positioned correctly take the second poster board piece, place it in front of the eyepiece, and see if the your optical device is projecting an image. If an image does appear onto the posterboard, then you’re all good. If that image is a little blurry, use the focus on the binoculars or telescope to focus the image.
The great thing with this approach is that you can adjust the size of your eclipse image by changing the distance of the second poster board from the eyepiece. When you’ve found an appropriate size, simply re-focus on the scope or binoculars and it should make the image crisp and clear.
Once your image is projecting and is focused. You’re all set. Ideally, if you’ve got that second tripod, affix the second poster board somewhere onto that tripod so you don’t have to hold onto it the whole time. Or, make your little brother hold up the second poster board. I don’t care.
One last recommendation: set all of this up in-advance of the start of the eclipse. Whether you do the pinhole projector or the telescope/binocular-viewer setup, you have enough time to construct it all once the big moment begins. If you wait last minute you may just miss it. Do it the night before and have everything ready hours in-advance. Test it. Make sure everything is perfect.
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