Some of the viewers I'll be trying to use
Posted by Chris in Tampa on 8/20/2017, 1:04 pm
"How to Make a Pinhole Projector

There are safe ways to view the sun. The simplest requires only a long box (at least six feet long), a piece of aluminum foil, a pin, and a sheet of white paper.

The length of the box is important: the longer the box, the bigger your image of the sun will be. To estimate how big the image will be, multiply the length of the box by 0.01. For example, if your box is six feet (72 inches) long, your solar image will be 72 x 0.01 = 0.72 inches in diameter, or about 3/4 inch."

From: https://www.exploratorium.edu/eclipse/how-to-view-eclipse

And more sites on how to make viewers:

https://www.jpl.nasa.gov/edu/learn/project/how-to-make-a-pinhole-camera/
http://www.skyandtelescope.com/observing/celestial-objects-to-watch/how-to-watch-a-partial-solar-eclipse-safely/

With the kind of viewers I made the image will be small and faint. You want a tiny pinhole, not really any larger or you let too much light in.

If you want a brighter image, you need to use binoculars or a telescope to magnify what appears on the paper. Don't view it through those, you let the sun pass through them and appear on a piece of paper. But then you risk damaging if left in the sun too long. I might try binoculars briefly, though even doing that it could damage the lens trying to make it appear on a piece of paper.

My dad and I tried to build a few different options. We wanted to try to use a viewer that was longer so the image should appear bigger, using that information at the top of this post.

We had various boxes and a few rolls of wrapping paper that we took the tubes out of.

The big viewer probably will not work. We'll need to lean it against something and it has to be lined up perfectly. We attached two boxes together. The pinhole on top of one, and a hole in each box to get to the second box where the paper is. My dad made a small hole between the boxes because he didn't want to totally ruin the boxes, but we might have to make that larger tomorrow.



Hole cut in box on the top with a piece of aluminum foil taped over it. Then a very small pinhole.



Inside the bottom box, the paper the sun should shine on. The whole thing is about 45 inches tall, so the sun might appear about half an inch wide on the piece of paper.



We should have had a much bigger hole between the boxes:



Making tube viewers out of wrapping papers tubes, with extra pieces of cardboard. One of the viewer examples used a long triangle shaped postal box. You could also attach paper towel tubes together perhaps, but that might get a little hard to make sturdy.



A hole for the tin foil to go on and the other piece of cardboard where the white paper will go for the sun to shine on.



A little opening to view the sun shining on the paper.



All taped up:





And then the other end taped up:



You can create the hole on the tin foil after you put it on.



Very tiny hole. It needs to be or you let too much light in and you won't be able to see the eclipse, probably just a round dot throughout.



Outside.



Using the tube viewers you can't look at the sun, so you look at shadows. You can see the viewer's shadow.



You want to point the pinhole at the sun and then using the shadow on the ground, try to make the viewer disappear. When it does, it should be lined up and you can see the small dot inside. It got cloudy while taking these, and was already hot this morning, so then I went inside.



With a powerful flashlight, here's a look inside the big box. Big box did better earlier when I tested it outside, but I didn't get a picture then. It's going to be faint. But it seems around half an inch.



Here is the flashlight inside one of the cereal box size handheld viewers. This is likely brighter than it should be. It's not the dot to left, not sure what that is. One to the right. Guess I need to cover some other areas of the box.



This is the same box with the flashlight further and on a lower setting. Likely closer to what it would be like. Very faint. Hard to take a picture of the little dot.



Here is one of the wrapping paper tubes. I put it on the counter and positioned the flashlight well down the counter. The flashlight has a square shaped setting and even when set to round sometimes the light itself seems square in these holes and the pinholes don't seem to be.



I will likely use the small attachment on my telescope or a pair of binoculars briefly. Maybe more binoculars rather than the telescope, as you're not supposed to use a plastic piece from a telescope, only if it is metal. I have various binoculars, some cheap, so I might try those and hold it and white piece of paper and see if I can see it that way. That would make things easier to see perhaps. I tried using the flashlight through some of that and it projects nicely.

It will be darker during the eclipse than when I tested this morning, so it should perhaps appear a little better than during the tests I did outside this morning.

I'm not sure if I really have any trees around where the light shines through and might show little eclipses all over the ground. This link from above shows that:
https://www.exploratorium.edu/eclipse/how-to-view-eclipse
As well as how you can simply use your hands.

I was initially going to put two tubes together, but I started with two different sized tubes and they weren't going together well. I wanted them sturdy. I should have used two of the same size and tried it. If the tubes are too narrow though, it won't appear well at the end probably. I had one wide tube and was going to put the narrow tube where the pinhole would be. I didn't think two narrow tubes might work and forgot to try.
32
In this thread:
Total Solar Eclipse on August 21st - Chris in Tampa, 8/11/2017, 9:08 pm
< Return to the front page of the: message board | monthly archive this page is in
Post A Reply
This thread has been archived and can no longer receive replies.