There’s only one atmosphere of pressure from inside to outside. Under the sea the direction is reversed and pressure is much higher.

Fry: "How many atmospheres can the ship withstand?" Professor: "Well, it's a spaceship, so I'd say anywhere between zero and one." s02e12

futurama comes to mind. the spacecraft can withsthand any level of atmosphere between 0 and 1

The one atmosphere that telescopes are looking through. It is nowhere near as problematic as looking through seawater.