Edge of solar eclipse path of totality may slightly shift, experts warn

US News

solar eclipse 2024

By Jesse O’Neill

Your opportunity to see Monday’s eclipse may have just gotten smaller.

A new calculation by John Irwin, a master in eclipse computations, suggests that the solar eclipse’s path of totality — where the moon will completely blot out the sun — is actually 600 yards narrower than the official NASA projections.

This means that if you were planning to watch the eclipse from a place on the edge of the path of totality, you might have an even shorter window.

Some spots will miss out entirely.

Based on this new data, locales that were expected to see the total eclipse for a few seconds — like Rome, New York; Effingham, Illinois; and Montreal’s Cité Jardin park — are now just out of the zone.

The change in the 115-mile-wide, 9,200-mile-long path of totality was first reported by Forbes.

A NASA scientist confirmed that the long-standing official map might not be entirely accurate and advised people right on the edge to travel a mile or so into the zone to guarantee they see the moon completely obscure the sun.

The cause of the discrepancy: disagreements about how big the sun is.

“Calculations that use a slightly larger radius for the size of the sun yield an eclipse path that is slightly narrower,” Dr. Michael Kirk, a research scientist in the Heliophysics Science Division at NASA’s Goddard Space Flight Center, told Thrillist Wednesday.

“This difference would only affect cities on the very edge of the path of totality, where blanket predictions are difficult, regardless.

“A few city blocks one way or the other could mean 20, 10, or zero seconds of totality.”

The zone of totality could also be slightly impacted by “uncertainty in the Earth’s rotation,” Kirk said.

“Traveling towards the center of the path of totality — even a mile or two — will quickly increase the length of totality that people can see.”

Any small nuance in the zone would not affect the vast majority of the estimated 34 million people who are expected to witness the total solar eclipse on Monday.

Many major US cities like Dallas, Indianapolis, Cleveland and Buffalo are still squarely in the center of the path, and will see nearly 4 minutes of complete darkness.

Southern parts of the US will actually see a slightly widened path of totality if Irwin’s projections are accurate, including 

San Antonio and Austin, where the Lone State State capitol’s Mckinney Falls State Park is suddenly now narrowly in the zone.

Several hours north from there the zone starts to narrow, squeezing Denton, Texas and Lewisville Lake slightly out of the blackout area.

As the totality zone snakes to the northeast, Effingham, Illinois, and Crawfordsville, Frankfort, Kokomo and Fort Wayne, Indiana, were set to lose a sliver of visibility — as were Canton, Columbus and Cincinnati, Ohio, according to Forbes.

In New York’s Finger Lake region, the small towns of Penn Yan, Dresden and Romulus were negatively impacted, and the city of Rome was now almost entirely squeezed out of the zone, the projections show.

In Canada, parts of Toronto, Montreal, Drummondville and Lumsden were also losing a piece of the once-in-a-lifetime show in the sky.

Irwin’s collaborator, Luca Quaglia, explained to Forbes that he believes their projection is more precise because they used a more accurate measurement of the sun and moon instead of widely used figures that are based on a calcuations of the sun’s size that has been used since the 1800s.

“Measurements and observations in the last decade have demonstrated that [the traditional measurement of the sun] is slightly too small,” said Quaglia, adding “There is evidence that the solar radius has changed over the centuries.”

He also maintained that the jagged edges of the Moon’s topography, which have now been exactly calculated NASA’s Lunar Reconnaissance Orbiter, would narrowly impact the path of totality, 

Still, there was no guarantee that the new measurements are completely precise. 

“How far outside the eclipse limits the solar corona ceases to be visible is anyone’s guess,” said Quaglia. “There is no experimental data to back any distance up.”

The longest period of darkness in the zone will be in Torreón, Mexico, where the sun will be blacked out for 4 minutes and 28 seconds.

By the time the eclipse is visible in Lake Placid, New York, the length of totality will have decreased to 3 minutes and 21 seconds.