The constellation Leo, 1603.
© Science Museum / Science & Society Picture Library
Illustration taken from 'Uranometria' (1603) by Johann Bayer, showing the zodiacal constellation of Leo (the Lion). German astronomer and lawyer Johann Bayer (1572-1625) invented the system for naming stars using letters from the Greek alphabet, a system still used today for the brighter stars - those visible to the human eye without the aid of a telescope. 'Uranometria' depicts the positions of nearly 1000 stars in addition to those identified by Tycho Brahe. A number of distant galaxies can be observed in Leo by astronomers, and the constellation is asociated with several meteor showers, most notably the Leonids, which occur in November every year.