HESPER, HESPERUS, in Astronomy, the evening star; an appellation given to Venus when she follows or sets after the sun. The word is formed of the Greek Ἑσπέρ; and is supposed to have been originally the proper name of a man, brother of Atlas, and father of the Hesperides.
Diodorus, lib. iii. relates, that Hesperus having ascended to the top of Mount Atlas, the better to observe and contemplate the stars, never returned more; and that hence he was fabled to have been changed into this star.