The Atlas Coelestis is John Flamsteed's folio of 28 copperplate engravings, published in London in 1729, sixteen years after the first Astronomer Royal's death. Across a hand-washed indigo sky, ivory line-figures of Rococo constellations drawn by Sir James Thornhill are incised, their stars picked out in gilt and scaled by magnitude. It is a design of classical restraint and celestial ornament — Baroque drapery over an engraved coordinate grid.