Milky Way. Optical image of the Milky Way in the constellation Cygnus, the swan. North is at top. The bright star at upper left is Deneb (Alpha Cygni). To its left is the North America nebula (NGC 7000), an emission nebula which glows red due to ionisation of the hydrogen gas it contains by radiation from hot stars. The three bright stars forming the wings of the swan are seen running from lower left to upper right. They are Gienah (Epsilon Cygni), Sahr (Gamma Cygni) and Delta Cygni. The Milky Way is the band of light crossing the sky formed from the millions of stars in the disc of our galaxy. This constellation is best seen in the summer in the northern hemisphere.