Corona Borealis is a small constellation in the northern hemisphere. In Latin, its name means the "northern crown." The main stars in Corona Borealis form a semicircular arc resembling a crown. The constellation was created by the Greek astronomer Ptolemy in the 2nd century.
In Greek mythology, the constellation is usually associated with the crown Dionysus gave to Ariadne, the daughter of King Minos of Crete, when she married him. Ariadne had left Crete with Theseus after helping him kill the Minotaur, but Theseus abandoned her pretty soon and, as she sat forlorn on the island of Naxos, Dionysus saw her and decided to marry her. After the wedding, Dionysus threw the crown into the sky, where the jewels turned into stars and the crown became a constellation.
In Welsh mythology, the constellation was called Caer Arianrhod ("the Castle of Arianrhod") and identified with the heavenly abode of Lady Arianrhod. The Cheyenne in North America called it the "Camp Circle," after the way they arranged their camps, in a semicircle. The ancient Chinese called it Kwan Soo, meaning "a cord." Australians identified Corona Borealis with Woomera, or the Boomerang.
Corona Borealis occupies an area of 179 square degrees and contains three stars with known planets. It can be seen at latitudes between +90° and -50° and is best visible at 9 p.m. during the month of July.
The brightest star in the constellation is 
alpha Coronae Borealis, also known as Gemma ("jewel"), Alphecca or Alphekka (from "nayyir al-fakka," or "the bright star of the broken ring"), Gnosia (from "Gnosia stella coronae," or "star of the crown of Knossos") and Asteroth, Astarte or Ashtaroth (from the Hebrew word for "idols"). Astarte is an eclipsing binary star system believed to be a stream star member of the Ursa Major Moving Group, or Collinder 285, a moving group of stars that share common velocities, travel in the same direction, and are believed to have a common origin.
beta Coronae Borealis, another binary star system, is the second brightest star in the constellation. It is also known as Nusakan, from the Arabic "an-nasaqan," meaning "the (two) series."
There are two other interesting binaries: 
zeta-1 and 
zeta-2 Coronae Borealis are a pair of blue-white stars, while 
nu-1 and 
nu-2 Coronae Borealis are a pair of orange giants.
Corona Borealis has several notable variables, including 
R Coronae Borealis and T Coronae Borealis. 
R Coronae Borealis is a yellow supergiant and a prototype of the R Coronae Borealis (RCB) class of variable stars, fading by several magnitudes (usually from magnitude 6 to magnitude 14) at irregular intervals. This is presumably caused by a build-up of carbon dust in the star's atmosphere, followed by the dust being dispersed by radiation pressure. The star is also known as the Fade-Out star or Reverse Nova.
T Coronae Borealis, also known as Blaze Star, is a spectroscopic binary star with a red giant component. It is a recurrent nova that usually has a magnitude of 10.8, but reaches magnitude 2 or 3 when it erupts, as it did in 1866 and 1946.
There are no bright deep sky objects in Corona Borealis. The Corona Borealis Galaxy Cluster, or Abell 2065, is a notable cluster that contains more than 400 galaxies, but the brightest ones are only 16th magnitude. The estimated distance between our solar system and the Corona Borealis cluster is approximately 1,200 million light-years.
Corona Borealis belongs to the Ursa Major family of constellations, along with Ursa Major
, Ursa Minor
, Canes Venatici
, Coma Berenices
, Leo Minor
Constellations directly bordering Corona Borealis are Hercules
and Serpens Caput