The Observatory is the home of the Great Beings during their years of self imposed exile. It is an immense space station, made of the strongest Exsidian, and powered by an engine designed by the first Elder Beings. The ship is divided into levels and decks that contain all the necessary facilities for observing the universe. It also has several levels that simulate different environments that the Great Beings use as testing rooms for any living creations.
Atop the Observatory is the Observation Deck where one can watch all the celestial bodies in motion as the ship passes by. It stretches the length of the ship, and has cone shaped apparatuses scattered across it that project holograms of the universe. One can zoom in on any specific part of the universe and watch whatever is happening there live, give or take a few seconds. These holograms also contain any data that was collected by the Mata-Nui robot prior to Makuta's takeover. The deck is completely open to space, as being a super being does come with some perks like not needing to breathe, or able to create your own supply of air at will.
Directly below the Observation Deck is the Living Quarters. Each Great Being has their own room, though some are larger than others. The rooms are organized along the outer edges of the Observatory with their doors facing a large common area that used to double as a mess hall until the schism. Now some rooms have been blown to pieces and it's common to see Great Beings bunking together or cramped in a single room, continually reinforcing it so that no one else can get in. The floor of the common area is cracked and covered in blast marks. The one area that hasn't been touched is the Elder Being's quarters, perhaps out of respect for a great leader.
Below the Living Quarters come each of the simulated environments. These are not so much 'simulated' as they are maintained. By means of a dimensional manipulation technology the Great Beings were able to cram inside the Observatory, objects that are larger than the ship itself. The first of these environments is Faux Bota. Faux Bota is an oval shaped mass of land that is dominated by an imposing volcano. Surrounding the volcano is a forest that stretches to the edges of the environment. This is the spot of one of the early tests of a prototype Opus. The release of so much energy burned a portion of the forest to the ground and left the earth in that spot scarred. You could see this if there was any light on Faux Bota. Due to the fighting on the upper levels, the circuits that lead to the false sun and stars have been damaged. Now the only light comes from the random sparks of electricity on the ceiling and the glowing eyes of a Muaka stalking its prey.
Beneath Faux Bota is Faux Aqua, a sea of water that houses as much aquamarine life as the Great Beings ever created on Spherus Magna or inside Mata-Nui. Unfortunately, much of that life has been slowly dying away. The broken circuitry has led to a faulty temperature system. Sometimes the water chills to near ice before shooting up past the boiling point. The glass walled tunnels, built for observing marine life, that crisscross Faux Aqua are not handling the strain well. Several of them have cracked and flooded already and others are expected to follow suit.
The last environment is Faux Bara. This is an area meant to be similar to the Great Desert of Spherus Magna. There are spiderwebs of canyons separated by stretches of shifting sand, and dry riverbeds. In comparison to Faux Aqua and Bota, Faux Bara hasn't suffered much damage from the lack of maintenance and fighting. Faux Bara draws its limited supply of water from Faux Aqua environment. Because of the rapid temperature shifts, it will occasionally snow, hail, or send down boiling rain. Not much of a shift, as the Rahi here (such as Nui Jaga and Sandbats) are used to extreme environments.
Perhaps the most dangerous level is the Laboratory. It was the site of many an experiment and test during the years before the schism. Aside from being where the Opus was developed, it also housed prototypes of dangerous creatures. In the wake of the schism, these creations have escaped and now run rampant in the lab. Some believe this to be the place where the thief took the Opus, but few are brave enough to traverse this area. No one know just what's down there, and as a result all the usual entrances to the lab have been sealed off. To enter, one would have to go through more unconventional means.
The final level of the Observatory contains the Engine Core, which was one of the first creations made by the original Elder Beings. It is a large, glowing crystal that has the ability to transform matter into energy extremely fast. So fast, in fact, that for small moments of time, the matter ceases to exist. When it bursts back into reality, it releases such a monumental burst of energy that the ship can be propelled at astronomical speeds. After the Elder Being was murdered, the Engine Core has ceased to function. Any attempts to break in have been futile, and currently the ship is running on auxiliary power. The Observatory can last indefinitely this way, but restoring the Engine Core to full functionality should be a high priority.
Stretching around the outside of the space station is the Maintenance Deck. It is a network of lifts and walkways that are used for facilitating repairs to the outside of the ship. It is also useful for getting to the different levels speedily. Normally, one would have to go down to each level through a central spiral staircase, but with the Maintenance Deck, you can just take a lift down to your desired level. In the case of the Laboratory and the Engine Core, however, it doesn't mean you're getting in.