Visitor's Guide to Yavin
Yavin and its Major Satellites
Yavin is a star system in the Outer Rim Territories. The Yavin system has three planets: Fiddanl, Stroiketcy, and Yavin. Fiddanl is a hot, toxic world. Stroiketcy is probably a large comet that was captured by the system, as it follows an extremely ellipsoidal orbit. It supports no life. Yavin itself is a gas giant with dozens of moons, three of which are capable of supporting life. Yavin Four is a lush, jungle moon with wide rivers and diverse forms of life. Yavin Eight is a mountainous moon with stretches of tundra and many varieties of rodentlike life. Yavin Thirteen is a desert moon with two forms of intelligent life: the reptillian Slith and the mammalian Gerbs. Both Are still in the primative stages of development.
The tranquillity of the jungle moon of Yavin Four, formerly the site of the Rebel Alliance's primary secret base, is once again disturbed bt the arrival of Jedi students under the tutelage of Jedi Master Luke Skywalker. He has established his Jedi academy in the Massassi temple ruins once used by the Rebels to house their small fleet of starfighters.
The nights of Yavin Four are seldom dark, since the jungles and mountains of the moon are bathed in the near-constant glow of Yavin's immense surface. Even when the sun is not shining directly on the gas giant, a diffuse glow still surrounds the planet, creating a shadowy twilight world on most nights. Occasionally, the Yavin gas giant eclipses the sun, plunging Yavin Four into the dark night most people are accustomed to.
A beautiful atmospheric phenomenon occurs in the early morining on Yavin Four, as a result of the moon's orbit around the gas giant Yavin. Light from the sun is refracted into primary colors when it passes through the upper atmoshpere of Yavin prime, and filters through the swirling mists which pool in the lowlands to create a shower of rainbows which only last a few minutes. They may be clearly seen from the Massassi temples occupied by the Jedi students.
Map based on drawings from The SW Technical Journal of the Rebel Forces
Yavin System description from A Guide to the Star Wars Universe by Bill Slavicsek
Yavin Four description from The Jedi Academy Sourcebook