In this video, I show how to build a pinhole projection viewer to safely view the sun or a solar eclipse, and how to use the viewer to calculate the actual diameter of the sun. Remember: NEVER LOOK DIRECTLY AT THE SUN. The video is organized into the following parts:
0:17 Timelapse of the April 8, 2024 solar eclipse as viewed from inside the viewer;
0:51 How to make the pinhole projection viewer;
5:21 How to calculate the diameter of the sun using the viewer; and
11:37 Data from our personal weather station showing outside temperature and solar radiation before, during, and after the eclipse.
A special "thank you" to Dr. Emily Maher, Professor, Department of Physics, Massachusetts College of Liberal Arts, for reviewing this video before publication.
Details:
0:17 Timelapse of the April 8, 2024 solar eclipse as viewed from inside the pinhole projection viewer: In this part of the video, you can see how the sunlight projects on the inside of the viewer to form an image of the sun, as the solar eclipse progresses. When the viewer is mounted in a fixed position pointing toward the sun, you will notice that the sun's image moves across the inside of the viewer. I had to reposition the viewer several times during the eclipse to keep the image within the viewing area inside the viewer. For reference, here is another video I uploaded, showing a timelapse of the April 8, 2024 solar eclipse filmed using an iPhone 15 Pro Max mounted on a tripod and with a solar photo filter clipped over the lenses: • Solar Eclipse Timelaps...
0:51 How to make a pinhole projection viewer: In this part of the video, I show how to make the viewer itself. You'll need a 3-ft or 4-ft mailing tube (I used a 4-ft mailing tube purchased from Staples), a sheet of aluminum foil, a small pin, a box cutter or other blade, some dark construction paper, a sheet of white paper or small-grid graph paper, and optionally a large rubber band.
5:21 How to calculate the diameter of the sun using the viewer: In this part of the video, I show how to use a measurement of the size of the sun's image in the viewer to calculate the actual diameter of the sun itself. NOTE that I am ignoring significant figures. The value used for the distance from the sun to the earth came from here: theskylive.com.... The comparison values used for the diameter of the sun came from NASA (science.nasa.g...) and from Space.com (www.space.com/....
11:37 Data from our personal weather station showing outside temperature and solar radiation before, during, and after the eclipse: In this final part of the video I show some graphs from our personal weather station. According to our personal weather station, the outside temperatures dropped from 73 deg. F. to 67 deg. F. (~23 deg. C. to ~19 deg. C.) during the first half of the eclipse and then rose again. And the solar radiation decreased from a peak of 1,073 W/m^2 down to 62.6 W/m^2 at the maximum 89% eclipse!