All winter long, and even during the first few weeks of spring, the mighty constellation Orion the Hunter has dominated the southern skies, but the seasonal celestial times are a-changing. The king of the celestial beasts, the constellation Leo the Lion, appears to have chased Orion and his entourage of bright stars toward the exits of the western horizon. Actually it's our Earth's orbit around the sun that's put Leo flying high in the southern sky. As the Earth continues its annual journey around our home star we're turning away from the direction of space that Orion and the prime winter stars occupy, and our gaze in April and May is now looking toward the stars of Leo.
Leo is definitely less flashy than Orion, but none the less it's a distinctive and famous constellation. Most people see it as a two part constellation. The right side is an easy to see backward question mark with the moderately bright star Regulus, the brightest star of Leo, marking the bottom dot of the query mark. It doesn't take a whole lot of imagination to see how the sickle of stars outlines the profile of a lion's head, with Regulus marking the heart of the giant heavenly feline. To the left of the lion's bust is a triangle of moderately bright shiners that supposedly outline the lion's derriere and tail.
Regulus, Leo's brightest shiner, is certainly not in the upper echelon of bright stars in the night sky. In fact, Regulus is a Latin name that translates to the "little king" or "the prince". Astronomically it's not all that small of a star though. It's nearly twice the diameter of our nearly million mile wide sun, and its interior nuclear fusion furnace is much more active than our sun. In fact, the outer layer of Regulus has a temperature of at least 20,000 degrees F, about twice as hot as our sun. That causes it to kick out 140 times more light than our home star. Regulus would be a whole lot brighter in our sky except that it's 80 light years away, with just one light year equaling nearly six trillion miles.
In most cultures Leo is depicted as a lion. Some of the earliest records we have of people making up constellation pictures come from ancient HYPERLINK "http://en.wikipedia.org/wiki/Sumerian_language" \o "Sumerian language" Sumerian culture, located in present day Iraq. Sketches of Leo the Lion have shown up in caves in that area.
In Greek and Roman mythology Leo the Lion was a huge legendary lion, (possibly on steroids?) that terrorized the countryside annihilating and devouring anything in its path. Many tried to bring down the ferocious giant lion and wound up in its digestive system instead, but the mighty hero Hercules was the end of the line for Leo. Hercules is actually depicted in a nearby summer constellation that I'll feature in the coming weeks. The tale of Hercules the hero is quite a story.
Other cultures have much different interpretations of the group of stars we see as Leo the Lion. Egyptians see Leo as their famous Sphinx, a strange mythological figure of half recumbent lion with a human head in the desert sun. The constellation Egyptians saw as the Sphinx was very important to them because in ancient times, when the sun passed into the stars of the Sphinx, that was the seasonal sign of summer that the life giving Nile River was about to go into its annual flood. In Peru the stars of Leo are supposed to picture a puma pouncing on its prey. In China Leo's a zodiacal horse. Christian cultures in the middle ages saw Leo the Lion as a reminder of the Biblical story of the prophet Daniel being thrown into a den of lions for his beliefs.
You probably won't have any trouble finding Leo the Lion in the high southern evening skies, but just in case you do, the waxing gibbous moon approaching its full stage can act as a guide for you this week. As you can see in the diagram, the moon passes just under Mars being chased by Leo on Wednesday. On Thursday and Friday the growing moon will slowly swing eastward, slipping just below the king of the celestial beasts mighty paws.
Diagram of the constellation Cassiopeia and Cepheus...Click