Sestina is a beautiful, oceanic world in the Antlia Sector recharted by the Pathfinder Ship Pegasus. It has 50 million human inhabitants and is a member of the New Commonwealth.
Sestina’s oceans are inhabited by the Memn; a species of hyper-intelligent jellyfish. The Memn are extremely adept at performing the calculations necessary to navigate in hyperspace. The human inhabitants were peaceful and moderately advanced.
The Sestina system also has a habitable ocean-moon orbiting a ringed gas giant (Envoi) that occupies the next orbit out from Sestina. This moon, called Envoi I is the location of the New Commonwealth base called Envoi Station, which was the location of a major (secret) New Commonwealth Intelligence Station during the Second Aurelian War. Envoi Station is a training base for Memn who volunteer to serve as navigators for the ships of the New Commonwealth and Free Worlds.
Sestina’s people are some of the galaxy’s strongest telepaths, probably as a result of prolonged coexistence with the Memn.