Bootes constellation. This constellation contains the fourth brightest star in the night sky, Arcturus (Alpha Bootis, lower right), although the third brightest, Alpha Centauri, is only third as it contains two bright stars that are indivisible with the naked eye. As a single star, Arcturus is the third brightest visible in the night sky. Bootes, the bear keeper, forms an elongated kite figure stretching from Arcturus to upper centre. At centre left is the constellation Corona Borealis, the northern crown. This is a small arc of stars centred on the blue star Gemma, or Alphecca (Alpha Coronae Borealis).