The Midnight Planet

Abstract

Choeroboscus preserves the following notice, which came down to him from Herodian (i 45. 14, ii 743. 24 Lentz):Μεσόνυξ Μεσόνυχος εἶς τῶν ἐπτὰ πλανήτων παρὰ τοῖς Πυθαγορείοις ὀνομάζεται. μέμνηται Στησίχορος(PMG 259).It has been almost entirely overlooked by historians of Greek astronomy. The only published discussion known to me is a short article by P. J. Bicknell in Apeiron (Monash University) ii 2 (1968) 10-12. He observes that it is a notice of considerable significance, and he makes some important inferences from it. The only planet mentioned in Hesiod and Homer, or in early poetry generally, is Venus, under the names ῾´ Εσπερος and ῾ Εωσφόρος. Bicknell notes that the name Mesonyx must have been chosen ‘on analogy with ’ those names; I would prefer to say, by antithesis to them. Hesperos was the luminary that only appeared in the evening, Heosphoros always presaged the dawn: Mesonyx was the planet that could be seen in the middle of the night.