Sizing Up A Solar Eclipse

by Tyler Molleur

HARDWICK – Three weeks ago, as I was visiting with family in Hardwick for lunch, I pulled open the utensil drawer to discover several pairs of specially designed light-protective glasses in storage: memorabilia from a solar eclipse on August 21, 2017.

“I thought I would save them for the next big event,” said my mother.

photo by Tyler Molleur | The eclipse of the sun reaches its maximum point (about 60 percent coverage) on August 21, 2017. Thursday’s eclipse is expected to cover 80 percent of the sun.

One of the biggest memories that stands out about that day was all the neighbors who took a moment to stand out on their porches to view the spectacular phenomenon of the moon blocking out light from the sun. Standing in amazement as the sun morphed into a narrow orange crescent and the light over the fields and hills south of the village briefly faded, everyone went silent for a few minutes.

photo by Tyler Molleur | Partial eclipse of the sun begins over Hardwick on August 21, 2017.

Solar eclipses occur with more frequency worldwide than we think. Many ingredients, however, must come together to optimize the viewing of the event. Therefore, solar eclipses that have relevance to our area are often spaced apart by several years.

The next eclipse that is visible to Vermonters occurs Thursday, June 10. The sight will be a tribute to early risers, as the sun rises at 5:04 a.m. and the peak of the eclipse occurs around 5:40 a.m.

In both the upcoming and previous events, Vermont remains outside of the narrow path where the moon covers all but the outer edges of the sun’s disc and creates a shadow Earth’s surface (umbra). Instead, we are treated to a view of the moon creating a partial shadow (penumbra). This makes the sun appear as a half-eaten cookie in the sky, which is still awe-inspiring, especially with Thursday’s event in proximity to sunrise.

Solar eclipses must happen when the new moon phase occurs and the side of the moon we view faces away from the sun. If this was the only requirement for an eclipse, we would theoretically have 12 eclipses per year. However, one must think of how the sun, the moon, and the earth interact to create these eclipses.

The moon’s orbit relative to the plane of orbit of the earth around the sun averages about five degrees, meaning that the moon does not always pass between Earth and the sun at every new moon phase. In many cases, the moon’s path stays well above or below the sun and out of view during the day.

The alignment of all three spherical bodies only occurs when the moon’s orbit crosses the ascending or descending node in its orbital path, creating the phenomenon of the moon blocking light from the sun. This of course, is also not equally visible from every surface of the earth at the same time. Only select regions will time the viewing to achieve eclipse conditions, and an even narrower geographical area will be treated to totality (full coverage) or annularity (if the moon does not appear large enough to cover the entire disc of the sun).

The final ingredient is the weather: will we see the eclipse through the clouds? For Thursday morning, expect skies to be mostly clear and more comfortable than the last few days. There should be a welcome break from the recent heat and humidity as a backdoor cold front sweeps through today with some showers, setting the stage for high pressure to move out the clouds and usher in some refreshing air from the north.

Looking ahead to 2024, we are in for a treat as northern Vermont will be in the path of totality for an eclipse on April 8, according to NASA. The view of this eclipse will feature a dramatic darkness, leaving behind light prominences fanning out from totally covered disc of the sun.

Regardless of the type of eclipse you may witness, it is important to practice safety in viewing the event. In general, it is never a good idea to look directly at the sun as the structures of our eyes can be easily damaged from the light.

When planning your viewing party for a solar eclipse, consider methods of viewing that protect your eyes from the sun. One way is to purchase solar viewers that meet ISO standards. Another option is to make a pinhole eclipse viewer using a shoebox or cereal box. Directions for making a pinhole viewer are easily found online. Happy viewing!