Custos Messium is a now obsolete constellation in the northern hemisphere, created in
1775 by Jérôme Lalande.
Between 1791 and 1801, French astronomer Jérôme Lefrançois de Lalande
put together a star catalogue containing 47,390 stars. As part of it, he designed
four new constellations.
Lalande's first creation, Custos Messium was first shown on a celestial globe he designed in 1775.
In the accompanying text, Lanade explained that the constellation was
a homage to his fellow countryman, astronomer Charles Messier, known at the time as the comet hunter.
The "harvest", Lalande referred to was Messier's record of (at the time) eight comets. "Messium" was meant as a punning reference to the name Messier. For that reason, the
constellation was often referred to simply as Messier.
Lalande picked a relatively uncharted area near the north celestial pole between the main stars of the constellations
Camelopardalis and
Cepheus, north of the main stars of
Cassiopeia.
It was the location of the first observation of the Comet of 1774 (now known as
Comet Montaigne, after his discoverer Jacques Montaigne or simply as C/1774 P1).
