Lacaille’s Reticulum


Lacaille first published the constellation Reticulum in 1756 on his planisphere of the southern stars and its accompanying catalogue, although there was some inconsistency between the two in its naming. On the chart it was given as le Reticule Romboide, as on the illustration below, while in the remarks following the catalogue he called it le Réticule rhomboïde, with the addition of a letter ‘h’ and some accents. The name was Latinized to just Reticulus (sic) on the second edition of the chart in 1763 which accompanied his final catalogue, Coelum Australe Stelliferum.

The constellation commemorated the cross-hairs in his telescope’s eyepiece which he used for measuring precise star positions. He showed a diagram of the actual device in the introduction to Coelum Australe Stelliferum.

lacaillereticulum.JPG

The illustration above comes from a copy of Lacaille’s map published in the Atlas Céleste of Jean Fortin. The spelling of ‘romboide’ is the same as on Lacaille’s original planisphere, i.e. without an ‘h’. (Image © Ian Ridpath.)