Brian Jones: Leo

The constellation of Leo can be seen high up in the southern eastern sky during mid-evenings in March and is really unmistakeable. It is one of the few groups actually resembling the object or character that it depicts, in this case the Nemean lion which Hercules slew as the first of his twelve labours. The whole group does indeed resemble a crouching lion, with the curve of stars upwards from Regulus depicting the head, mane and paws. This curve of stars is often known as the Sickle. At the opposite end of the constellation we have the triangle of stars formed from Denebola, Coxa and Zosma which form the lion’s hindquarters and tail.

The story associating the lion with Hercules is that told in Greek mythology, although there are other accounts of how the lion came to be among the stars. One of these comes down from the ancient Egyptians who associated the group with the heat of summer. This was because members of the lion population left the hot desert regions for the cooler areas surrounding the Nile during the summer months, at great inconvenience to the communities living on the banks of the river!

Leo is the leading spring constellation and contains over a hundred naked-eye stars. The brightest star in the group is Regulus, a name which means ‘Ruler of the Heavens’ and which was given to the star by the Polish astronomer Nicolaus Copernicus. Regulus is a prominent blue-white object which shines from a distance of around 75 light years and is the 21^st brightest star in the sky.

Slightly fainter than Regulus is Denebola, a star which shines from a distance of around 36 light years and whose name is derived from the Arabic for ‘Tail of the Lion’. Indian astronomers referred to it as the ‘Star of the Goddess Bahu’ while Persian astronomers knew it as Avdem, meaning ‘The One in the Tail’. Astrologers of long ago held Denebola as something of an opposite to Regulus, associating it with misfortune and bad luck. White in colour, Denebola was regarded by Chinese astronomers as one of the Seats of the Five Emperors.

Regulus is a prominent blue-white object which has a fainter companion, seen as a rather yellowish star, quite close to Regulus itself. The pair can be resolved in small telescopes. Another of Leo’s bright stars is the orange-red Algieba, a name derived from the Arabic Al Jabbah meaning ‘The Lion’s Forehead or Mane’. Algieba has a fainter yellowish companion star which can be seen through a small telescope. As with most stars, optical aid, such as binoculars or a small telescope, is required to bring out the colours of Algieba and its companion. Binocular users might also like to try their hand at resolving the two stars forming Tau, located someway to the south of the main constellation. Tau itself is an orange star and has a fainter companion which should be visible in binoculars.

The star Algenubi derives its name from the Arabic for ‘The Southern Star in the Lion’s Head’. This star, along with nearby Mu and Adhafera, all three of which have a yellowish tinge, form the main outline of the lion’s mane. Through binoculars they each present a pretty sight under dark, clear and moonless skies.

So, there we have it – Leo, as the name suggests, takes pride of place among the stars of the spring night sky. Until next month, happy stargazing!