constellation

Boötes

목동자리
The Herdsman · A kite-shaped figure
Spring · in the eastern sky

Boötes, the kite-shaped herdsman. Arcturus, the fourth-brightest star in the night sky and a red giant, leads the herdsman who drives the bear.

Arcturus
Star pattern · J2000.0
✧ See Boötes in the sky →

Science

The science

Arcturus, the chief star of Boötes, is the fourth-brightest star in the night sky, a red giant about 25 times the Sun's diameter. Belonging to the Milky Way's halo, it races along in a direction unlike the other stars; it has been drawing nearer to us for about the last 50,000 years and is now beginning to move away again. The 1933 Chicago World's Fair opened by catching this star's light in a photoelectric cell to switch on the exposition's lamps.

Mythology

How it became a constellation

Boötes also carries the meaning "the one who drives the bear." The most famous reading pictures him leading his hunting dogs and forever chasing Ursa Major across the sky. Another legend tells of Philomenus, foster son of the harvest goddess Demeter, set among the stars for inventing the plow. The name of its chief star, Arcturus, means "guardian of the bear" in Greek.

Observing Guide

how to observe

🔭 How to find it

Follow the gentle curve of the Big Dipper's handle onward across the sky and you arrive at the bright orange star Arcturus ("arc to Arcturus"). This is the lead star of Boötes and the brightest star in the spring night sky, with the other stars fanning above it into a necktie or kite shape. Extend the curve farther and it carries on to Spica in Virgo, the two together forming the "Spring Arc."

What to look for

Boötes is a constellation rich in bright stars but almost devoid of notable bright deep-sky objects, so it rewards attention to the stars themselves rather than to nebulae or clusters. As compensation, Izar (Epsilon Boötis), a little above Arcturus, is a beautiful double star pairing a yellow primary with a blue companion — nicknamed "Pulcherrima," the loveliest — and a popular target for small telescopes.

📍 Where to see it (US · Canada · UK · Australia)

From the US, Canada and UK, Boötes climbs high from the eastern to the southern sky on spring and early-summer evenings (May–July), with brilliant orange Arcturus shining almost overhead from Canada and Britain. Its northernmost stars barely set from higher latitudes, so the constellation stays well placed for much of the year. From Australia, Boötes appears low in the northern sky and inverted on winter evenings; Arcturus still shows clearly, but the figure's upper reaches sit very low near the horizon.

Stars

Main stars (J2000.0 equatorial)
ArcturusRA 14.26h · Dec 19.2° · m-0.1
MuphridRA 13.91h · Dec 18.4° · m2.7
IzarRA 14.75h · Dec 27.1° · m2.4
DeltaRA 15.26h · Dec 33.3° · m3.5
NekkarRA 15.03h · Dec 40.4° · m3.5
SeginusRA 14.53h · Dec 38.3° · m3.0
RhoRA 14.53h · Dec 30.4° · m3.6
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