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What to Look For During the Solar Eclipse

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By Rick McMahan

A total solar eclipse happens when the moon passes between the sun and Earth and completely blocks the face of the sun. Central Vermonters located near the center of the moon’s shadow when it hits Earth will experience a total eclipse. The length of totality for the Barre and Montpelier area will be about 1 minute and 30 seconds. Farther north and west in Vermont the length of totality is greater. Farther south and east, viewers will only see a partial eclipse.

The start of the partial eclipse will be at 2:15 p.m., with totality at about 3:28 p.m. The outgoing partial eclipse phase will end at 4:37 p.m..

The 400 Factor

The 400 Factor is what allows the moon to completely block the sun during total solar eclipses. The sun is approximately 400 times wider than the moon, but it is also approximately 400 times farther away, so they appear to be the same size in our sky.

In the future, as the moon’s orbit moves farther away from Earth, there will come a time when there are no more total eclipses. When this happens, there will be only annular eclipses, where the moon appears as a dark disk on top of a larger, bright sun disk, creating what looks like a light ring around the moon. The next total eclipse for Vermont will be in 2106.

Protect your eyes during the partial portion of the eclipse. Looking at the sun without proper eye protection is unsafe except during the brief total eclipse phase. This happens only within the narrow path of totality. At all other times, it is safe to look directly at the sun only through special purpose solar filters, such as “eclipse eyewear,” that comply with the transmittance requirements of the ISO 12312-2 international standard. It is not safe to look at the sun with ordinary sunglasses, even very dark ones. 

Baily’s Beads

Just before totality as the moon continues to move across the sun, several points of light shine around the moon’s edges. Known as Baily’s Beads, these are light rays from the sun streaming through the valleys along the moon’s horizon. Baily’s Beads are short-lived and may not last long enough to be noticeable to all observers of the total solar eclipse. 

Immediately after, the Baily’s Beads will disappear until eventually only a single bright spot will remain along the edge of the moon’s shadow. This bright spot resembles the diamond in a giant diamond ring formed by the rest of the sun’s atmosphere. Totality is almost here — but keep those eclipse glasses on until the moon is completely in front of the sun.

Comet 12P/Pons-Brooks

During totality the sky will become very dark, as if it were dawn or dusk. If the skies are clear, observers can see the sun’s outer atmosphere, the corona, with their own eyes. The corona is otherwise too dim to be seen against the bright face of the sun. Also, the planets Jupiter, Venus, and Mercury might be visible, plus in ideal conditions, a comet, 12P/Pons-Brooks, will be visible.

As the moon continues to move across the face of the sun, there will be a brightening on the opposite side from where the diamond ring shone at the beginning. This is the lower atmosphere of the sun beginning to peek out from behind the moon, and it is the signal to stop looking directly at the eclipse. Make sure your eclipse glasses are back on — or you are otherwise watching the eclipse through a safe, indirect method — before the first flash of sunlight appears around the edges of the moon.

Rick McMahan is a NASA Solar System Ambassador in the volunteer program created by the Jet Propulsion Laboratory of Pasadena, California.

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