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Boötes constellation: The herdsman of the sky

Galaxy NGC 5529 (FGC 1735) is located in the northern sky constellation Boötes (the Herdsman), approximately 140 million light-years from Earth. Bob Franke captured this image from the Focal Pointe Observatory in Chino Valley, Ariz., from April 3 to May 17, 2013.
Galaxy NGC 5529 (FGC 1735) is located in the northern sky constellation Boötes (the Herdsman), approximately 140 million light-years from Earth. Bob Franke captured this image from the Focal Pointe Observatory in Chino Valley, Ariz., from April 3 to May 17, 2013.
(Image: © Bob Franke / Focal Pointe Observatory)

Boötes is a constellation in the northern hemisphere containing one of the brightest stars in the night sky, Arcturus. Boötes is an ancient Greek word that roughly translates as the ox-driver, or herdsman. The two dots over the second "o" indicate that both "o's" should be pronounced separately as "boh-OH-teez."

The herdsman can be seen driving his great plow, the Big Dipper, in a great circle around the north star, Polaris, along with his two trusted hunting dogs, which are represented by the constellation Canes Venatici on his right flank. Boötes also stands proudly next to three constellations: Hercules and Corona Borealis are on his left, while Virgo lies below.

Boötes is best seen in the springtime, rising in the northeast after sunset. A simple way of finding the constellation is to look along the handle of the Big Dipper away from its spout, arcing to the bright orange star Arcturus, forming the base of the constellation Boötes, which may look like a kite to some.

What's in this patch of sky

Modern astronomers use constellations to divide the celestial sphere into different areas (like state lines and borders on a map). Organizing the sky this way allows astronomers to easily find points of interest for their telescopes to spy on.

The patch of sky Boötes occupies faces away from the plane of our Milky Way galaxy and contains few astronomical objects. In fact, the constellation contains one of the most empty places in the known universe, the Boötes Void. This mysterious void is an area of the universe 250 to 330 million light-years across that is nearly empty, containing only a handful of galaxies, according to NASA

Closer to home, there are three meteor showers associated with the constellation Boötes. The Quadrantid meteor shower is the first meteor shower of each year, typically occurring within the first week of January. The fiery display peaks for only a few hours and can be seen coming from the area between the constellation Boötes and the Big Dipper. The two other showers found in the constellation are known as the Boötids and occur in late January and June, although they're less brilliant than the Quadrantid showstopper that precedes them.

From midnorthern latitudes on spring evenings, the Big Dipper, Boötes, and Virgo can be found high in the sky from the northeast to southeast. Follow the red arrows from the Dipper's handle to arc to Arcturus and the kite-shape of Boötes, and then proceed to speed to Spica in Virgo. (Image credit: Starry Night software)

The Bear Keeper

Boötes is home to the fourth-brightest star in the night sky, a red giant called Arcturus. The star is a distant neighbor to our solar system, a mere 37 light-years away, or 218 trillion miles (350 trillion kilometers). Arcturus is more than 113 times brighter than our sun, despite being only 1.5 times as massive, according to Jim Kaler, a professor emeritus at the University of Illinois at Urbana-Champaign. 

Arcturus is a dying star in its last stages of life. As a red giant, it no longer fuses hydrogen into helium in its core; instead, it fuses heavier elements such as helium and carbon, causing it to swell to almost 25 times the size of our sun.

The ancient Greeks told many myths about the stars of Boötes, including the story of Arcturus, the son of Zeus and Callisto, and the story of Icarius, the grape grower who was given a divine recipe by the Gods to make wine. 

"People treat the sky like a menu and select patterns that are distinctive, recognizable, and useful. What they choose depends on where they live and what they need," the astronomer Ed Krupp wrote in his book "Beyond the Blue Horizon" (Harper Collins, 1991). "To the Greeks, these stars were better known as the Bear Keeper or Bear Driver, and were associated with Ursa Major and Ursa Minor, the two celestial bears," Krupp wrote.

To the Mi'kmaq people, who are indigenous to Canada's Maritime Provinces, the stars found in the constellation Boötes also represented hunters chasing a great bear around the northern sky. But unlike the ancient Greeks, the Mi'kmaq saw many hunters in the form of birds within Boötes, each star representing a bird native to their land. Throughout the seasons, the birds pursue the great bear around Polaris in an eternal hunt — symbols of seasonal change and renewal.

In modern times, it may be more appropriate to reinterpret these stars, seeing them as something that's more familiar to us in our day-to-day lives. One popular interpretation is to see Boötes as a giant ice cream cone. The frosty treat is being licked by a cosmic tongue forming the constellation of Corona Borealis. 

But no matter if you see Boötes as an ice cream cone, a herdsman or a hunter, it is certainly a constellation worth watching throughout the seasons.

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