As promised two days ago, it's finally time for a new constellation post! This one is going to be all about horses, so if you're a horse lover, rejoice. If not, well, then there is at least some interesting mythology here.

Equuleus, or 'little horse' is the second smallest of all of Ptolemy's constellations. It is depicted by solely a horse's head, and seems almost hidden away behind the much larger horse constellation Pegasus. There is a mythological reason for this hiding behavior: Equuleus is said to represent Hippe (Ἵππη), or Melanippe (Εὐίππη), daughter of the kéntauros Kheiron. She became pregnant and could not let her father know. As such, she begged the Gods to be transformed into a mare. From Hyginus's Astronomica:
"Euripides in his Melanippe, says that Melanippe, daughter of Chiron the Centaur, was once called Thetis. Brought up on Mount Helicon, a girl especially fond of hunting, she was wooed by Aeolus, son of Hellen, and grandson of Jove, and conceived a child be him. When her time drew near, she fled into the forest, so that her father, who supposed her a virgin, might not see that she had given birth to a grandchild. And so when her father was looking for her, she is said to have begged the power of the gods not to let her father see her in childbirth. After the child was born, by the will of the gods she was changed into a mare which was placed among the stars."
He also gives another reason for her change:
"Some say that she was a prophetess, and because she used to reveal the plans of the gods to men, she was changed into a mare. Callimachus says that because she ceased hunting and worshipping Diana [Artemis], Diana changed her into the shape we have mentioned. For the reason above, too, she is said to be out of sight of the Centaur, who some say is Chiron, and to show only half her body, since she didn’t want her sex to be known."
The constellation is also known as Eguus Primus, the 'first horse' because it rises just before Pegasus. Because it rises first, it is sometimes identified as the offspring of Pegasus, Celeris, whom he had with his wife, Euippe (or Ocyrrhoe). The second child out of that marriage was Melanippe, a common female name when associated with horses, as it means 'mare'.
The third and last horse that this constellation is connected to it the horse that was born the moment Poseidon's trident struck the ground in the battle for patronage of the city of Athens:
"The common tradition about Poseidon creating the horse is as follows : -- when Poseidon and Athena disputed as to which of them should give the name to the capital of Attica, the gods decided, that it should receive its name from him who should bestow upon man the most useful gift. Poseidon their created the horse, and Athena called forth the olive tree, for which the honour was conferred upon her. [Serv. ad Virg. Georg. 1.12.]
The constellation Equuleus is visible at latitudes between +90° and −80°, and best visible at 21:00 (9 p.m.) during the month of September.