Moon shadow: Yale observatory offers viewing for annular solar eclipse

The Great North American Eclipse, Part I, is coming to a telescope near you on Saturday.

More formally called an annular solar eclipse, the celestial event will chart a course through western parts of North America on Oct. 14. It will look like a ring of fire in the sky over the western United States; here in Connecticut, weather permitting, it will look more like Pac Man’s high achieving brother.

Yale’s Leitner Family Observatory and Planetarium will offer public viewing of the eclipse through the observatory’s telescopes from noon until 2 p.m.

This week’s eclipse is a precursor for an event bigger eclipse — particularly for the Eastern U.S. — next spring. On April 8, 2024, there will be a total solar eclipse that will be visible from Mazatlan, Mexico, through the eastern half of the U.S., and on to Newfoundland in Canada.

For more information, there is a NASA website devoted to the eclipse.

In anticipation of these astronomical events, Yale News caught up with Michael Faison, director of Yale’s observatory, academic director for the Yale Summer Program in Astrophysics, and senior lecturer in the Department of Astronomy in Yale’s Faculty of Arts and Sciences.

How often do annular solar eclipses occur?

Michael Faison: A partial, hybrid, annular, or total solar eclipse happens somewhere on the Earth on average twice a year. A bit less than half of those times that the center of the moon lines up with the center of the sun, as seen from some place on Earth, you get an annular eclipse instead of a total eclipse. This is because the moon is a bit too far away in its orbit to completely cover the apparent disk of the sun.

What will we see from Connecticut?

Faison: In Connecticut, about 20% of the disk of the sun will be covered by the moon at about 1:15 p.m. [EDT]. There’s a path across the U.S. and Mexico that will see an annular eclipse.

Is the observatory offering public viewing?

Faison: Yes, if the weather is clear, the observatory will be open from 12 p.m. until 2 p.m. on Saturday, October 14.

What does an annular solar eclipse look like, and how does it differ from other types of eclipses?

Faison: Unlike a total solar eclipse, an annular or partial solar eclipse must be viewed at all times with solar eclipse glasses or a pinhole projection. In the path of the annular eclipse, you would see the moon in front of the sun with a ring of sunlight around the dark moon. In places where we only get a partial eclipse, like in Connecticut, it will appear that the moon has taken a bite out of the sun. The daytime sunlight will not decrease noticeably.

Since most people don’t have eclipse glasses and may not even know that the partial eclipse is happening, I think most people will experience it as noticing something odd about the shadows underneath trees. The gaps between the leaves make small pinhole-like openings that can project an image of the sun onto the ground. Normally, these images are round, and people don’t think about them, but during a partial eclipse, these projections of the sun look like crescents, and people notice that something odd is happening.

How long will this eclipse last?

Faison: People in the path of the annular eclipse will see the annulus effect for just a few minutes. The partial eclipse lasts for about two hours.

What is the fascination for the public, and even for experienced astronomers, in seeing an eclipse?

Faison: I think it’s interesting that we know the science of the orbits of the moon and the Earth well enough to predict the alignment very precisely in space and time, and we’ve had this ability for 400 years! So I find it reassuring, for example, when a partial solar eclipse or a lunar eclipse starts at the exact second predicted by laws of celestial mechanics.