Out beyond Neptune, there are numerous dwarf planets and other objects orbiting the cold, distant reaches of our solar system. You probably already know Pluto, but astronomers have discovered a number of new dwarf planets in recent years, including Eris, Makemake and Haumea. There are surely many more to find.
The Catalina Sky Survey take images of around half of the night sky almost every night, searching for these Trans-Neptunian Objects (TNOs). Then, astronomers need to sort through all of the pictures, looking for faint signs of movement that might indicate a TNO. Citizen scientists are helping out with this effort through the Catalina Outer Solar System Survey project. Compare images taken at different times, and see if you find something exciting.