The Planetarium Puzzle is a puzzle that Harry Mason can come across during his search in Silent Hill: Shattered Memories. The puzzle is found on the second floor of Midwich High School, should Harry choose to enter the planetarium as opposed to the art studio. In order to continue further into the school, Harry must find a way to unlock the door out of the planetarium using the machinery found inside.
The puzzle centers around the device in the center of the school planetarium. Turning on the device illuminates the ceiling of the room with the stars found in many constellations. The device can be turned on by pressing the bottom switch on the podium beside it. The top switch on the podium temporarily reveals the lines that connect the stars to form constellations. The machine that projects the stars, the globe in the center of the room, can be rotated in order to show all of the stars in the sky
Inside of the room Harry can also receive a voicemail message by approaching the seat with scattered papers. The message plays a past lecture, where the teacher mentions the constellation "Ursa Minor" or "Little Bear", and the students react. In order to solve the puzzle, Harry must rotate the projector to show Ursa Minor. After doing so and pressing the top switch, The constellation will be lit up, along with a secret message left behind by a student. The message contains the phone number 555-2327, and calling it unlocks the door to exit the planetarium.
Additionally, portraits of all the projected constellation line the walls, should the player not know the shape of Ursa Minor. Alternatively, the player can simply rotate the projector to display the star "Polaris", or the "North Star", as it is found in the constellation Ursa Minor and is the brightest star displayed.