For centuries the appearance of the constellation Leo the lion in the sky has heralded spring for the northern hemisphere. But the constellation is an ancient one, with references to a celestial lion in this part of the sky that go back over 2000 years. As might be expected, there is a rich amount of lore and history connected with Leo.

 Many cultures around the world have seen these stars as a lion, and at first this might seem a little strange, or at least coincidental, but such is not the case. There is a logical reason why so many different cultures associated a lion with this area of the sky.

 During the time between about 2300 BC and 1BC, the Sun was in this area of the sky during the hottest part of the summer. Back then, people thought the stars were much  closer than they are, and they firmly believed that it was the combined heat of Leo's brightest star, Regulus, and our Sun which made the summer so hot. The fierceness of the summer heat was compared to the fierceness of a lion. It was also during the hottest part of the summer that earthly lions migrated to the banks of the Nile river to find relief from the heat. As precession (the wobble caused by the Earth's rotation on its axis ) changed the appearance of the sky, the Sun moved out of Leo and into  the constellation Canis Major, the Greater Dog during the hot time of the summer. Then the bright star Sirius was believed to add to the Sun's heat. Sirius is called the dog star because of the constellation it is in, so the days when Sirius was believed to add to the summer heat were called the dog days.

 Leo is one of the constellations along the ecliptic, the path the Sun appears to take as the Earth moves along in its orbit. When astrologers formed the zodiac out of the constellations along the ecliptic, Leo was one of the twelve constellations, and was referred to as the House of the Sun. It was considered a fortunate sign and supposedly ruled over the heart. However, physicians seemed to feel otherwise, at least some of the time. Medicine was thought to be poisonous if given during the time that the Sun resided in Leo. Physicians were strongly opinionated about the effects of Leo, and went so far as to state that even a bath was harmful if taken during the time of the Sun in Leo!

 The brightest star in Leo is Regulus. That name seems to have been given the star by the fifteenth century astronomer Nicolus Copernicus. Prior to that the star was known along the Euphrates as "The Flame" no doubt another reference to the summer heat. A more popular title for the star was the "heart of the lion." Regulus is a bright blue-white star about 3 times the diameter of the Sun.

 During the middle of April you can find Leo high in the southern sky  around 9PM. Regulus is the brightest star in that area of the sky, so it is pretty easy to spot. Also, the right portion of the constellation forms a conspicuous backwards question mark. Pick a warm clear night and go out and find an ancient constellation that is rich in history.