Olympus is a hidden starsystem near the center of the map, just below Star 26.  The same officer has to be Enlightened and Chosen to jump there.  First, your science officer must successfully scan for Olympus in order to detect it, and then you will be able to select it from the jump menu.

Benefits:

• can hire up to 2 crew per turn, per officer (and can "charm" both at the same time) 
• 18 of the 32 trade goods are purchased here, often at higher prices!
• automatically earn extra favor in your chosen field
• lots of ancient ruins for adventuring
• safety from Dybuk (although I don't believe this has been tested since the Dybuk rules were changed)