A constellation representing the river Tigris, a real river of Mesopotamia which joins with the Euphrates in the modern Iraq. The constellation was introduced in 1612 by the Dutchman Petrus Plancius on the same globe as the river Jordan (Jordanus) made its first appearance. The celestial Tigris began at the neck of Pegasus and flowed between Cygnus and Aquila (an area now occupied by Hevelius’s later invention Vulpecula), ending by the right shoulder of Ophiuchus. Like Jordanus, it became forgotten during the 18th century and was not shown on the atlases of Johann Bode.

Tigris running from Pegasus, at right, to the shoulder of Ophiuchus at left, as seen on a planisphere by Isaac Habrecht II in his book Planiglobium coeleste ac terrestre (1628). (Image courtesy ECHO, Berlin.)

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