Early-rising Massachusetts residents looking low on the eastern horizon Thursday could catch a glimpse of the sun “with a bite taken out of it” due to an annular solar eclipse. At its 5:33 a.m. peak in Boston, the moon will block about 73 percent of the sun.
“For where we are on the earth, and the positions of the sun and the moon and the earth, it’s just happenstance that Massachusetts is not going to be in the path of the most shadow. So we’re only on the edge,” said Quinn Sykes, Boston University’s observatory manager. “We’re going to get some of the shadow. We’ll see the sun get darkened by the moon as the moon passes between us and the sun.”
An annular, or ring-shaped, eclipse happens when the moon is farthest from Earth. Due to its distance, it seems smaller and doesn’t entirely block the sun, leaving a “ring of fire” around the edge.
The eclipse will begin to darken the sky around 5:07 a.m. and last for about an hour and a half, Sykes said. The moon will move across the sun during this time, reaching the peak of 73 percent and then slowly letting more light through.
Sykes said it was important that people who want to see the eclipse wear eclipse glasses and not stare into the sun.
Eclipses are not uncommon but rarely pass over Massachusetts, Sykes said. The next one will be visible here in 2024.
Where the shadow of an eclipse lands “varies widely,” he said. “The earth is spinning, so where it hits on the earth is all over the place, and most of the time it’s gonna be covering water because most of the earth is water.”
Residents may notice darker skies on Thursday morning but their ability to see the eclipse depends on cloud cover and whether the horizon is visible, Sykes said.
“It may appear to you like a really dark storm cloud, even though there’s not a cloud in the sky,” he said.
Residents in the northwest portion of the state will have a greater chance of seeing a more complete eclipse, Sykes said.
“The further northwest you go, the closer you get [to the path], the more the sun will be covered,” he said.
Kristie Smith, a meteorologist with the National Weather Service Boston, said it will likely be partly cloudy on Thursday morning. The cloudiest areas would likely be the Cape and Islands, she said, while north and west of Boston has a higher chance of clear skies.
This graphic shows what the eclipse will look like to viewers in various cities:
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