The size of the sun using pinhole imagery

In summary, the conversation discusses the potential effects of the intensity of the sun on the ability to create an image using a pinhole and a piece of construction paper. It is noted that the sun's intensity may be a factor in the difficulty of creating a clear image. The conversation also mentions using different distances and sizes to try and improve the image. An additional suggestion is given to use smoked glass to experimentally test the effects of light intensity on the image.
  • #1
taylorb
2
0
Does intensity of the sun affect this? I keep trying to do it, and when you have a square shape you should still see an image of the sun.. right? Well it is not working! I live in a place with VERY intense sun and no clouds... could this be the problem?

Any help!? Thanks so much...
 
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  • #2
What, exactly, are you seeing? How big is the hole? How far apart are the hole and your imaging plane?
 
  • #3
OK... what I did was cut a square in the center of a piece of stiff construction paper. Then I covered the square with a piece of tin foil. Then I punctured the middle of the piece of tin foil with a sewing needle (very small). When I went outside I started out with the pinhole about a foot away from the piece of white paper on the ground that I was trying to project the image onto. I got a tiny dot... slightly bigger than the pinhole itself... very difficult to measure. So I moved the pinhole further away and closer to try and make the image bigger with very little change. So I have put it very close and about four and a half feet away. We are also meant to try it with a small square and it is still meant to show an image of the sun, but when I make a small square that is exactly what is projected on the piece of white paper!

Thanks!
 
  • #4
Taylor,

As a rough guide, basic geometry gives the spot size as

[tex]y = D_H + L \theta[/tex]

where [itex]D_H[/itex] is the diameter of the hole, [itex]L[/itex] is the distance between the hole and the image plane and [itex]\theta[/itex] is the angular diameter of the Sun (in radians). In order to get a "good" image of the Sun, you will need to arrange for [itex]L \theta[/itex] to be larger than [itex]D_H[/itex].

Good luck!
 
  • #5
experimentally speaking, you may put some smoked glass otside the pinhole to check if light intensity affects the spot size. that is one of the way to do physics.
 

1. How can you determine the size of the sun using pinhole imagery?

The size of the sun can be determined by measuring the diameter of the sun's image produced by a pinhole camera and using basic geometry to calculate its actual size.

2. What equipment is needed to capture pinhole imagery of the sun?

To capture pinhole imagery of the sun, you will need a pinhole camera, a tripod or stable surface to mount the camera, and a light-sensitive material such as photographic film or a digital camera.

3. Can pinhole imagery be used to accurately measure the exact size of the sun?

While pinhole imagery can give a relatively accurate estimate of the size of the sun, it may not be precise enough to determine the exact size due to factors such as atmospheric distortion and the size of the pinhole used.

4. How does the distance between the pinhole camera and the surface affect the size of the sun's image?

The distance between the pinhole camera and the surface affects the size of the sun's image by changing the angle at which the sunlight passes through the pinhole. The closer the camera is to the surface, the larger the sun's image will appear.

5. Are there any safety precautions that should be taken when capturing pinhole imagery of the sun?

Yes, it is important to never look directly at the sun or point the pinhole camera directly at the sun. It is also recommended to use a solar filter or eclipse glasses to protect your eyes and equipment. Additionally, be aware of potential fire hazards if using a digital camera with a zoom lens pointed at the sun.

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