|English name||Boreal Crown|
|alpha Coronae Borealis||Gemma||magn. 2,2||RA: 15h 34m 41.26s||Dec: +26° 42' 53.2"|
|Description||Small constellation between Hercules and Bootes. It is characterized by a half-moon shaped line of stars, among which Gemma is conspicuous, similar to a precious stone on the crown (this star is also known with the name of Alphecca).
In the constellation there are two interesting variable stars. The first one, R Coronae Borealis, is normally of sixth magnitude, but it can quickly go down to the fourteenth, to return to the original shine after some months. The second one, T Coronae Borealis, usually revolves around the tenth magnitude, but in 1866 and in 1946 it increased its brightness up to touch, respectively, the magnitude 2 and 3: it is probable that there will be other eruptions.
Remarkable is also a pair of double stars: zeta Coronae Borealis, a couple of blue stars, and ny Coronae Borealis, formed by two orange giants.
|The constellation represents the crown that Ariadne wore when she married the god Dionysus.
Ariadne was the daughter of Minos, king of Crete, and she is famous because she helped Theseus to kill the Minotaur, the monster with human body and bull head. The Minotaur had confined in an extremely complex labyrinth: who wanted to beat him, therefore, not only had to defeat him, but he also had to avoid to remain trapped in the same jail. When Theseus entered the labyrinth to face the Minotaur, Ariadne gave him a ball of thread, so that he tied it to the entrance and unwound it while advancing inside the building. So, after having killed the monster, Theseus was able to find the exit by simply rewinding the thread.
But Theseus was ungrateful towards Ariadne: after having set sail together with her, he abandoned her on the Nasso island, in the middle of the Aegean Sea. While the young girl was sitting sadly on the beach, Dionysus saw her and fell in love with her: after their wedding, the god launched the crown worn by Ariadne in the sky, where the jewels that adorned it were transformed in stars forever.