Tigris (constellation)
The Tigris River ( lat. Tigris ) is a constellation in the northern sky that is not one of the 88 constellations recognized by the International Astronomical Union (IAU) .
The Tigris begins in the western part of the constellation Pegasus , includes the entire constellation Fox (Vulpecula) and some eastern stars of the constellations Hercules and Serpent Bearer .
The brightest stars of the constellation are: 72 Ophiuchi 3.71 m , 109 Herculis 3.85 m and 1 Pegasi 4.08 m . The remaining stars are only very faint, a maximum of 4.2 m in magnitude, mostly 5 m in magnitude or weaker.
The river Tigris was depicted in 1612 by the Dutch theologian, astronomer and cartographer Petrus Plancius on a celestial globe made by him, as a filling constellation between eagle , Pegasus, swan and Hercules. In addition to the mythical Eridanus after Ptolemy, who was named by Keyser Nile , Plancius introduced the Jordan and this river is believed to be one of the four rivers of Paradise .
The heavenly Tigris bears no resemblance to the true course of the earthly river Tigris . Probably for this reason, and also because there was already a river in the sky, the fox introduced by the Danzig astronomer Johannes Hevelius was preferred as the filling constellation for this star area.
In Europe, the Tigris can be seen in the night sky in summer.