The constellation of the Swan (Cygnus) offers a figure of characteristic cross. It is called sometimes "the cross of North".
One can imagine this swan the tended neck, spread wings, his axis in the axis of the Milky Way.
The nozzle of the swan is represented by Albireo(Bêta Cygni), double star.
The tail of the swan is represented by Deneb (Alpha Cygni, Deneb means "Arabic tail") magnitude 1,2 and which is one of largest and of most luminous of the supergéantes blue-white.
Parallely to axis of the Swan and on its line extends a dark nebula which darkens the Milky Way and divides it into two, it is the "Slit of the Swan" still called the "Bag with coal of North". It continues in the Eagle and Ophiucus (the Serpent eater) while widening.
For Deneb, one can leave the Small Pan and cross the meander of the neck of the Dragon. Deneb is 45°from Pole star, it is thus circumpolar always quite visible in all seasons.
One should not confuse it with Véga (the Quadrant) which is another brilliant star in the vicinity. Véga is on the left nozzle of the Swan (Albireo) with 15° approximately (a hand, isolated fingers). Véga is slightly further away from Polar (51°).
Deneb forms with Véga and Altaïr (the Eagle) a triangle, well-known under the name of "Triangle of summer".
Greek mythology is at the origin of the Swan. It is said that Zeus took the shape of the Swan to allure beautiful Léda, queen of Sparte. Their union produces two eggs from which on left hand the twins Castor and Pollux and on the other hand Helen of Troy.
