Plate taken from the 'Illustrated London News', describing the solar eclipse of 28 July, 1851. The first view (fig 3) shows the Sun's corona and prominences around the dark body of the moon during the total eclipse, about thirty seconds before the reappearance of the Sun. The second (fig 4) shows 'Baily's Beads' along the bottom of the Moon at the end of the eclipse. The Moon does not have a perfectly smooth surface, so when it covers the Sun during an eclipse, the Sun's light can be seen pasing along valleys on the lunar surface. The short-lived effect, which resembles beads or diamonds on a ring, occurs just before or after totality, and is named after Francis Baily (1774-1844), the British astronomer who first recorded the phenomenon in 1836.
© Science Museum / Science & Society Picture Library