Has the path of Monday's total solar eclipse moved?

The reality is they these areas along the outer edges of the path won't have a very good total experience under any version of the maps. Even the tiny amount of uncertainty in any of these eclipse calculations translates to hundreds of feet or more on these maps. But most importantly, because circles are round.

As we look at a eclipse maps with their lines defining the limits of the path, it's easy to forget that these areas are  fuzzier in reality. Observations in 2017 found those paths to be off prompting improvements in calculations.

Keep in mind that any eclipse calculation is ultimately predictions because there is still a lot even about our own solar system we don't fully understand yet.

When an eclipse begins and ends and whether the Moon will completely cover the Sun creating a total eclipse, ultimately comes down to the size and position of the Sun and the size and position of the Moon.

Like the spaghetti plots that the WRAL weather team shares showing different models predictions of hurricane paths, the different eclipse maps are built from slightly different values for critical variables in the model.  Each has

Irwin's calculations use a slightly larger number for the Sun's size producing an eclipse path closer to 114 miles wide than 115 through much of the country.

If you are heading out to a spot along the path to experience the total solar eclipse, this probably wont impact you much. Best views of the eclipse are from near the center of the path where the period of totality is greatest, up to 4 minutes 20 seconds or more. Along the edges, the experience is mostly of a partial eclipse with totality lasting seconds if at all. This is true of any version of the map.

Keep in mind that totality is seen inside the Moon's elongated 100+ mile wide circular shadow as it moves at up to 1,600 mph across the Earth's surface.  Near the center line, and the center of that circle, totality lasts much longer.  Near the edges only a tiny part of the circle passes over.

It all begins with the position of the Earth, Moon, and Sun. Many calculations start with assuming the Sun and Moon are perfect circles, which they are not, and then adjust for the shape. Like the Earth and pretty much any celestial body that rotates on its axis, the Sun and Moon are a bit fatter at the equator.  Astronomers call this "limb correction"

The Moon's surface is not smooth though, so to further improve predictions, the hills and valleys along the limb (the outer edge of that fatter in the middle circle) must be considered. Evidence of those valleys is seen just before totality as the last rays of sunlight pass through them creating an effect known as "Baily's Beads", named for Francis Baily, a British astronomer who first described the effect in 1836.  The last ray of light through the last valley is known as the "diamond ring" phase.

When looking at past and future eclipses, the calculations get even more complex as variations in the rotation of the Earth must be factored in as ΔT (delta T).