Broken Annular Baily's Beads Simulation

Baily's beads are bright pinpoints of sunlight peeking through lunar valleys along the silhouette edge of the Moon during a solar eclipse. They are named for astronomer Francis Baily, who described them in detail in a report to the Royal Astronomical Society in 1836. The beads appear a few seconds before and after totality (when the Moon completely blocks the Sun) or annularity (when the Moon is completely encompassed by the bright edge of the Sun).

The April 8, 2005, hybrid solar eclipse is neither entirely total nor entirely annular. Along part of its path, in the transition between total and annular, the disk of the Moon is both too small to completely cover the Sun and too large to be completely surrounded by it. Instead, Baily's beads are continously visible on first one side of the Moon and then the other. The resulting eclipse phase is described as beaded or broken annular.

Traditional eclipse calculations can't be used to map this transitional part of the eclipse path because they don't account for the mountains and valleys on the lunar limb that cause it. A 2024 paper published in the Astronomical Journal describes a new method of eclipse calculation that makes it possible to map the transitional, broken annular path. This method was used to locate a point on the 2005 hybrid eclipse path where a broken annular occurs and to simulate its appearance.