Blue Prince: Planetarium Room Guide
Image Credits: Dogubomb, Blue Prince
The Planetarium is a hidden room accessed through the Observatory, and while it doesn’t look like much at first, it comes with a powerful bonus: ending your day here gives you +2 Stars. It’s one of the few ways to boost your star count just by planning where you sleep.
Read More: All Rooms in Blue Prince
How to Access the Planetarium
Go to the Observatory
Use both the upper and lower dials on the telescope to adjust its position
Align it so the telescope stretches across to the ledge above
This will unlock a hidden compartment, revealing the Planetarium
It’s not marked on the floorplan until you solve this puzzle so you’ll need to interact with the telescope to make it appear.
What the Planetarium Does
It grants +2 Stars if you end your day inside the room
Contains a clue:
“A new constellation appears when you reach 50 stars.”
Reaching 50 Stars unlocks a new method for redrawing rooms, giving you more control over your floorplan
Stars are used for unlocking advanced Observatory perks, constellation effects, and hidden mechanics
The Planetarium is one of the only rooms that passively buffs your long-term progress without draining Gems or Steps.
Why It’s Worth Using
Stars are hard to get—this gives you a guaranteed way to farm them
Helps you reach the 50-star threshold, unlocking new drafting effects
Ending your day here is easy to plan around if you build it near your end-of-day path
Pairs well with planning builds or any strategy relying on redrawing or constellation upgrades
Final Blurb
The Planetarium is quiet, out of sight, and easy to miss but ending your day there makes the stars just a little closer. If you're chasing deeper constellations or better rerolls, it’s worth the detour. Sleep under the dome, and the manor might just look different tomorrow.
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