Scorpius
Scorpius, with the red heart Antares. Here are dazzling clusters toward the galactic center and the myth of the scorpion that felled Orion.
Science
The scienceThe chief star Antares is a red supergiant about 700 times the Sun's diameter. Placed where the Sun sits, it would reach beyond the orbit of Mars, and because it glows red like Mars, it was named in Greek for meaning "the rival of Mars (Ares)." At the twilight of its life, it is expected one day to explode as a supernova. Scorpius sits in the direction of the Milky Way's center, making it the most dazzling constellation, densest with stars and clusters; it holds the open clusters M6 (the Butterfly Cluster) and M7 (the Ptolemy Cluster), among others.
Mythology
How it became a constellationWhen the giant hunter Orion grew arrogant, boasting that "he could hunt every beast in the world," the earth goddess Gaia grew angry and sent a small scorpion. The scorpion stung Orion's heel and brought him to his death, and the gods set both heroic adversaries among the stars. But they placed them on exactly opposite sides of the sky so the two constellations would never meet, and so in the spring and summer, when Scorpius rises in the east, Orion flees and vanishes into the west.
Observing Guide
how to observe🔭 How to find it
On a summer evening, low in the southern sky, look for a red first-magnitude star — that is Antares, the scorpion's heart — with stars curving around it like a fishhook or an S, so closely resembling a real scorpion that it is easy to recognize. Antares glows red like Mars and is nicknamed "the rival of Mars," so you can tell them apart by color. The curve runs from the pincers at the head to the stinger at the tail's tip, right beside Sagittarius to the west.
✨ What to look for
Near the tail's tip (the stinger) sit two bright open clusters side by side — the "Butterfly Cluster" (M6), like a butterfly with wings spread, and "Ptolemy's Cluster" (M7) beside it — which fit into a single binocular field. Next to the lead star Antares lies the bright globular cluster M4, which even a small telescope resolves into stars. Facing the center of our galaxy, this region is especially rich in the Milky Way and star clusters.
📍 Where to see it (US · Canada · UK · Australia)
From the US, Scorpius crawls low across the southern sky on summer evenings (June–August), Antares reaching only about 25–30°, and its stinger drops near or below the horizon; from the UK and Canada the tail barely clears the horizon or is lost in haze, cutting the scorpion short. From Australia, by contrast, Scorpius is a showpiece — it passes high overhead during the southern winter, the whole scorpion on full display with the Milky Way behind it.