Lacaille’s Telescopium

Lacaille described Telescopium as representing the great astronomical refractor at Paris Observatory which, in common with other large refractors of the day, had an exceptionally long tube to combat chromatic aberration and was suspended from a mast by ropes and pulleys. This illustration comes from a copy of Lacaille’s chart of the southern stars published in the Atlas Céleste of Jean Fortin. (Image © Ian Ridpath.)