Baily, Francis (1774-1844)

British astronomer. He described the light effect called Baily's beads, observable during a total eclipse of the Sun, in 1836.

Baily was born in Newbury, and apprenticed to a firm of merchant bankers in London; then he set out to explore unsettled parts of North America. On his return to England 1798 he became a stockbroker, but retired 1825 in favour of full-time astronomy. In 1820 he became a founder and first secretary of the Astronomical Society of London, later the Royal Astronomical Society. In 1827 he was awarded the gold medal of the society (of which he was president at the time of his death) for revising their star catalogue. He travelled to Italy 1842 and was again able to see his beads during a solar eclipse. He was not the first to have noticed the beads, but his description of the 1836 eclipse was so exciting that it sparked a renewed and lasting interest in eclipses.

Baily began to publish his astronomical observations 1811. He was the author of an accurate revised star catalogue in which he plotted the positions of nearly 3,000 stars. He also measured the Earth's elliptical shape.