The Astronomers are characters from Bubble Guppies. They are a lobster and crab who only appear in "The Moon Rocks!" They love looking at the moon and running the planetarium. Goby meets them on his way to school, and they show him the moon through their telescope. Goby forgets his rock collection and the girl astronomer gives it back to him. The lobster reappears at the Guppies' field trip to the planetarium, where she returns Goby's rock collection, with a moon rock as an addition.