Partial Solar Eclipse Comes to East Lansing

Monday, August 21, 2017, 7:15 am
Aron Sousa

Residents of and visitors to East Lansing will be able witness a partial solar eclipse this afternoon. While there are parts of the country where the eclipse will be total, in East Lansing people can observe the moon covering about 80% of the sun.

The moon will begin to cross in front of the sun about 1:00 p.m. local time. Starting then, the moon will cover more and more of the sun until it covers its East Lansing maximum of 80% at 2:24 p.m. After the maximum, the moon will begin coving less and less of the sun until the partial eclipse ends at 3:45 p.m. (Close readers of ELi will recall previous coverage of East Lansing partial solar eclipses.)

It will not be safe to look directly at the sun at any point during the eclipse. That said, it will be safe to observe the eclipse using “eclipse glasses,” a welding shield, or a pinhole camera. There will be an eclipse watching party at the East Lansing Public Library where eclipse glasses will be available while supplies last.

The simplest, safe way to observe the eclipse in East Lansing is with a pinhole camera or projection as previously described in ELi. To make an eclipse-viewing device, an East Lansing resident should use a safety pin to make a single hole in the center of an index card and hold the card so the sun shines through onto a smooth, white surface (like a second index card). During the eclipse the light and shadow on the card will be a crescent, which is the image of the sun and moon during the eclipse.

There is a nice NASA video on making a more sophisticated but still homemade pinhole camera. While the NASA pinhole has many charms, intrepid ELi readers can accomplish the same images with any object with small hole. The index card described above is cheap and easy, but the holes of a saltine cracker will work just as well, and the cracker is edible, which is an advantage over most index cards. This reporter believes that Ritz crackers would work as well as saltines. Even overlapping tree leaves will form the equivalents of pinholes and leave crescents on the ground. The reader is challenged to see what interesting patterns could come from using the holes of a kitchen colander as pinholes.

In a solar eclipse like this one, the moon passes directly between the sun and earth casting a shadow on the earth. The full shadow cast by the moon completely covering the sun in a total eclipse is called the umbra, as shown in the diagram above. This is what people in areas with a total eclipse (like Nashville, Tennessee) will see.

East Lansing residents will be in partial shadow, called the penumbra, and will see only a sunny crescent with the moon covering part of the sun. In East Lansing, as noted above, the moon will cover about 80% of the sun, making it quite dark around the 2:24 p.m. eclipse maximum in East Lansing.