Arcturus ( \ / ɑrkˈtjʊərəs \ / ; α Boo , α Boötis , Alpha Boötis ) of the constellation Boötes is the brightest star in the northern celestial hemisphere .
Arcturus ( or α Boo , α Boötis , Alpha Boötis ) of the constellation Boötes is the brightest star in the northern celestial hemisphere .