Comet Observatory
The Comet Observatory is one of the many areas from the Wii videogame Super Mario Galaxy. It acts as the 'hub' area, similar to Peach's Castle from Super Mario 64.
It is found in the Gateway Galaxy and is where Princess Rosetta is found. Much like Peach's Castle in Super Mario 64, or Delfino Plaza in Super Mario Sunshine, certain parts of the observatory are unlocked as Mario acquires Grand Stars. This is because the Grand Stars are used to power a large becaon in the middle of the observatory. Once all seven Grand Stars are acquired, the observatory will have enough power to travel toward the center of the universe.
There are many domes scattered throughout the observatory. The domes are used to access the galaxies. Galaxies are accessed by either feeding some pink Luma, and getting more Power Stars. The domes are the Terrace, the Fountain, the Kitchen, the Bedroom, the Engine Room, and the Garden. According to the Lumas the domes are used to view the cosmos.