The reason why, they explained, is due to calculations about the size of the sun.
Luca Quaglia, a collaborator with Mr. Irwin, told the wire service that older eclipse calculations use a solar radius of 959.63 arc seconds. But Mr. Quaglia said it may be too small.
“Measurements and observations in the last decade have demonstrated that this value is slightly too small,” he told Forbes, adding that Mr. Irwin uses a solar radius of 959.95 arc seconds, which, according to the Forbes article, will cut about 2,000 feet from the path of totality’s edges.