 <unk> 1600 , the names of the constellations were used to name the stars in the corresponding regions of the sky . The German astronomer Johann Bayer created a series of star maps and applied Greek letters as designations to the stars in each constellation . Later a numbering system based on the star 's right ascension was invented and added to John Flamsteed 's star catalogue in his book " Historia <unk> Britannica " ( the <unk> edition ) , whereby this numbering system came to be called Flamsteed designation or Flamsteed numbering . 
