The Leo Constellation: Regulus, the Sickle, and the Lion Heracles Couldn't Cut

The Leo constellation is one of the rare zodiac constellations that genuinely resembles what it is named for: a backwards-question-mark of stars called the Sickle traces the lion's mane and chest, with a triangle of fainter stars trailing behind it for the hindquarters and tail. At the base of the Sickle sits Regulus, "the little king," one of only four stars the ancient Persians ranked as a Royal Star. This is the fifth entry in a twelve-part series walking through the actual constellations behind the twelve zodiac signs, following the crab before it.

The Sickle and Regulus, Leo Constellation's Royal Heart

The Sickle asterism, six stars curving like a backwards question mark, is the easiest part of the Leo constellation to pick out, and it maps directly onto the lion's head and mane. Regulus sits at the bottom curve of the hook, a blue-white star system about 79 light years away and, despite the small "little king" name, one of the brightest stars in the night sky at magnitude 1.36. Persian astronomers around 3000 BCE named it one of the four Royal Stars, along with Aldebaran, Antares, and Fomalhaut, each one assigned to guard a cardinal direction and a season. Regulus drew the spring watch, sitting close enough to the ecliptic that the Moon, and occasionally the planets, pass directly in front of it.

The Nemean Lion Heracles Could Not Cut

Babylonian astronomers already called this patch of sky the Great Lion more than three thousand years ago, one of the oldest constellations recognized across multiple ancient cultures. Greek myth folded in Heracles's first labor: King Eurystheus sent him to kill the Nemean lion, a beast whose hide no blade, arrow, or spear could pierce. Heracles gave up on weapons entirely and strangled it with his bare hands, then used one of the lion's own claws, the only thing sharp enough, to skin it. He wore the pelt as armor for the rest of his labors, and Zeus placed the lion among the stars to mark the labor that started the whole sequence.

Why Is Leo One of the Few Constellations That Actually Looks Like Its Name?

Because the brightest stars happen to fall in roughly the right places, which is not true for most of the zodiac. Cancer has no star brighter than magnitude 3.5 and needs real imagination to read as a crab; Leo's Sickle and its trailing triangle are bright enough to trace a recognizable crouching-lion silhouette with nothing more than a dark sky and a star chart. It is one of the few zodiac constellations where the shape sold the myth, rather than the myth being layered onto a shape that needed one.

Regulus's Slow March Out of Tropical Leo

Regulus itself has barely moved in a human lifetime, but the tropical zodiac has moved relative to it. Precession, the 25,800-year wobble of Earth's axis, drags the tropical zodiac's boundaries westward against the fixed background of stars at a steady rate, and by around 2011 that drift had carried the tropical Leo-Virgo boundary far enough to put Regulus on the Virgo side of the line. The star still marks the heart of the constellation Leo; it simply no longer sits inside the calendar sign that shares its name.

Anyone with a Sun, Moon, or rising sign in Leo can see exactly where it falls relative to Regulus and the Sickle with a free natal chart.