On this day in 1836, astronomer Francis Baily made a famous observation while viewing an annular solar eclipse in Scotland. Studying the eclipse from Inch Bonney in Roxburghshire, he noticed bright spots around the Sun’s limb. He reported “a row of lucid points” that he compared to “a string of bright beads” or “the ignition of a fine train of gunpowder.” In his honor, that phenomenon is known as Baily’s beads. It’s caused by light at the edge of the solar disk peeking through the Moon’s mountainous and cratered surface. The beads in the photo were captured in Oregon during the total solar eclipse of 21 August 2017. (Photo credit: NASA/Aubrey Gemignani)
