Giovanni Hodierna was an Italian astronomer at the court of the Duke of Montechiaro whose De Admirandis Coeli Caracteribus (1654) describes some 40 objects found with a simple Galilean refractor of magnification 20. Hodierna discovered the open clusters now known as M6, M36, M37, M38, M41, M47, NGC 2362, NGC 6231, and NGC 6530 (the cluster associated with the Lagoon Nebula) and several comets, and made the earliest surviving drawing of the Orion Nebula, in which three of the Trapezium stars are shown. His astronomy seems always to have verged toward astrology, and titles on astrology bulk large in his corpus of work.