This week offers us the opportunity to locate three of the fainter constellations that are linked by myth: Corvus, the crow; Crater, the cup; and Hydra, the serpent. Corvus is one of the oldest recognised constellations, dating back to Babylonian star charts from at least 1100BC. Hydra was also recognised by the Babylonians, although Crater is a slightly later invention.
What these constellation lack in bright stars, they make up for in backstory. In classical Greek and Roman myth, Corvus was tasked to fetch water for Apollo but the bird dallied to eat figs. In concocting an excuse for its lateness, the crow grabbed a snake and told Apollo that the serpent was guarding the water. Apollo saw through the lie and banished them all into the sky, where Corvus now sits on the tail of Hydra, just out of reach of Crater and the refreshing water inside.
The chart shows the view looking south from London at 2200BST this evening, although the view will be almost identical any night this week. In the southern hemisphere, the constellations are much higher in the north-western sky. From Sydney, Australia, by 2100 AEST, Hydra stretches downwards, with its head almost reaching to the western horizon.