The El Nanth system was the largest artifact known in the Federation until the discovery of the Dyson Sphere by the Enterprise D (the Jenolen never reported her find 75 years earlier.) The six worlds orbit the sun in the same orbit equidistant from each other. Five of the worlds are teraformed, only the largest, Savanna, is not teraformed. It is also recorded as the only world in the rosette that was originally in this orbit. Common names for the six worlds are clockwise from Savanna looking down from the solar north; Savanna, Veldt, Aurora, Meadow, Eliyssum, and Glade. The Rosette has an orbit of 3.2 standard Earth years. Axial tilt is only 2 degrees, and the orbit is round. This means that the Rosette has no seasons. Climate runs from tropical to temperate at the poles. The Ane don't live around the poles much, and a great deal of that land is turned over to temperate agriculture. The vast fully automated farms that produce El Nanth's major export labor in an eternal growing season.
According to the Ane the Rosette is a work commissioned 760,000 years before the 24th century in exchange for ideas the Builders had no insight into. The Builders have since been revealed. They requested UFP membership in 2395 and are based at the Three Suns Station, an artificial planet that the Builders call home.
The total Ane population at El Nanth is approximately ten billion. About one million non-Ane are in permanent or semi-permanent residence. The Ane move in herds of varying size. Except for the two cities and the farm areas the rest of the planets are totally natural. No effort is expended on "improving" the land. Vast trackless plains broken by seas, lakes, forest bands, and mountains.
One item that is important to note is El Nanth weather. The rosette worlds orbit a blue-white sun. the distance from the primary assures that the temperature is within Class M limits. However five times the ultraviolet radiation strikes the surface of El Nanth than does the surface of Earth. Local life is adapted. Ane have a tough hide and bright blue mucus membranes. The cornea of their eyes reflect violet and higher frequency light. All native life forms are likewise adapted.
Humanoids must use adaptive technology to survive. The average human left naked under El Nanth would not last a full day. The desert aba, made of a ultraviolet reflecting material, has been adopted as common overdress for anyone leaving cover. Sunscreen in excess of SPF 100 is strongly recommended for anyone leaving the cover of buildings. The hotels in Crystal City have a dispenser in the shower for sunscreen, as does every home or apartment.
The last weather feature of note is the terminator storms. Due to heavy ionization of the atmosphere during the long days a line of storms will tend to follow the terminator as the planets roll. the storms are not an unbroken line, nor will conditions produce them every day. But you can generally count on a two in three chance of rain as evening approaches. All El Nanth worlds share the same weather patterns.
The Year is 778.66 days (1168 standard stardays) long. New Year is marked when Savanna is in conjunction with El Nanth and Faldath the brightest star in the local sky. The year is divided into 20 "months" of 40 or 39 days. days (local) The months have mental symbols for the Ane. They are named for the last people through El Nanth that bothered, the Sharrdin: Bat, Bi, Hiru, Lau, Bost, Ssei, Zazpi, Zortzi, Bederatzi, Hamar, Hamaika, Hamabi, Hamahiru, Hamalau, Hamabost, Hamasei, Hamazazpi, Hemezortzi, Hemeretzi, and Hogei. It starts with Bat with 40 days and alternates with 39 day months.
El Nanth is protected by 10 Falcon class cutters, 6 Stingray class frigates, and the weapons of Builder Station. Any number of Starfleet ships may be added to this total depending on what and who is in the space dock.
The last "weapon" is the Sunlens. An asteroid defense system that is activated from an unknown location. The Sunlens is a focused beam of solar energy that could melt the best ship any known power could produce with a single shot. However, there is great difficulty in aiming the Sunlens at a target moving at relativistic speeds on an unpredictable course. Against any ship that can maneuver it isn't a viable option.
Builder Station is the oldest and largest of the El Nanth stations. It is the left over construction shack used during the building of the Rosette. It has been used by many civilizations since. All have left their mark on it. Builder Station is currently undergoing a through refurbishment by the Builders themselves.
Aurora Station is the interface with the Aurora Mining system. It is the only way to enter the mines and is the only way anything leaves the mines. The mines themselves have no surface opening and are run as if the surface of the planet was dangerous to access. The station is heavily shielded and armored.