The Tardanus constellation. Image Credit: Alessio Govi

In 1736 French astronomer Pierre Charles Lamonier (1715-1799) journeyed with Pierre Louis Maupertuis and Alexis Clairaut on their geodetical expedition for measuring a meridian arc of approximately one degree’s length, to Torne Valley in Lapland. On his return to Paris, France he produced the constellation of Le Renne, the reindeer, also known as Tarandus. To form this constellation he grouped together northern stars near the constellation of Cassiopeia.

Although Le Renne appeared on some maps it was not universally adopted; so the case of the disappearing reindeer adds to the greater mystery of that rotund man in red who turns up at this time each year. The crater Le Monnier on the Moon is named after him, the astronomer that is.