Inside Leo the Lion

We're now more than a week into the spring season (even if, meteorologically, in some parts of the country it's still very much wintry), and high in our current evening sky the most famous stars of spring are to be found making up the constellation of Leo, the Lion.

The most noteworthy star of this distinctive pattern is the bluish-white Regulus. According to Richard Hinckley Allen (1838-1908), an expert in stellar nomenclature, this star was known in Arabia as Malikiyy — "the kingly one." Yet, Regulus was seemingly always associated in ancient cultures with royalty and kingly power. Copernicus has been credited with giving the star its present name, a diminutive of Rex, or king, which may also relate to the four so-called "Royal Stars" (with Aldebaran, Antares and Fomalhaut) all situated about 90 degrees apart on the sky.

As the brightest star in Leo, first magnitude Regulus has been almost universally associated in ancient cultures with the concept of royalty and kingly power. This star lies in the handle of the so-called "Sickle of Leo," a star pattern resembling a large reversed question mark. Regulus is 77 light years distant; meaning that the light you see emanating from it tonight started on its journey toward Earth back in 1931, when Herbert Hoover was U.S. President, and Spain became a republic with the overthrow of King Alfonso XIII. The diameter of Regulus is estimated to be about five times that of the Sun; its luminosity 160 times greater.

Algeiba ("the Lion's Mane") is in the curve or the blade of the Sickle, and appears as a single star to the naked eye. However, as a telescope of only moderate size will clearly show, it is really one of the most beautiful double stars in the sky. It should really be observed in twilight or bright moonlight to reveal the contrasting colors ? one star has been said to be greenish, the other a delicate yellow. Others, however, have described different hues such as pale yellow and orange; reddish and golden yellow and even pale red and white!

The Sickle, when rising and climbing the sky, as it is doing now, is seen cutting upward. This year, there is also planetary interloper nearby in yellowish-white Saturn. Located to the left (east) of Regulus and shining more than twice as bright, Saturn is always a show stopper with its spectacular ring system, visible even in a small telescope.

Eastward from the Sickle there is a right triangle of stars that also belong to Leo. At the eastern point of this triangle you will find Denebola ("The Lion's Tail"). To modern sky watchers the Sickle outlines the majestic head and mane of a great westward-facing lion, with the triangle forming the lion's forequarters. He is crouching in the regal pose somewhat resembling the enigmatic Sphinx. Astronomer Henry Neely (1879-1963), for many years a popular lecturer at New York's Hayden Planetarium, would often use his electric pointer to draw attention to these stars and then would exclaim: "Behold! Here is the lion known as Leo. A conception that was familiar to the peoples of many lands long before a certain motion-picture company adopted him as its trademark."

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.