When this exchange happens during the final batter in *Return of the Jedi* (1983), how was “north” determined within the structure of the Death Star?

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> **LANDO:** There it is. All right, Wedge, go for the power regulator on the **north tower**.
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> **WEDGE:** Copy, Gold Leader. I'm already on my way out.
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From *Star Wars: Complete Locations* (2016):

[![Image from Star Wars: Complete Locations showing the Death Star II's polar column](https://i.stack.imgur.com/cZoP0.jpg)](https://i.stack.imgur.com/cZoP0.jpg)

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> **1** The primary stage focused on assembling components necessary for construction of the main reactor core—approximately one-tenth the diameter of the entire structure—**and the immense cylindrical polar column**, which served to distribute power and stabilize the Death Star's rotational capabilities.
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> *Star Wars: Complete Locations* (2016), page 166, "Death Star II", emphasis added
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In *Return of the Jedi*, we see the Rebels making their attack at the center of the area marked "Reactor core" on the diagram (indicated by hand-drawn red circle). Since it's connected to the "Polar column", the north tower is the tower connected to the north pole, which in space is less ambiguous than "the upper tower".

The asymmetry is made clear in the hologram of the Death Star II in the Rebel briefing:

[![Image from Return of the Jedi showing a hologram of the Death Star II's reactor core](https://i.stack.imgur.com/XOu5I.jpg)](https://i.stack.imgur.com/XOu5I.jpg)

[![Image from Return of the Jedi showing the Death Star II's central reactor core](https://i.stack.imgur.com/HMbKI.png)](https://i.stack.imgur.com/HMbKI.png)
The same way as on Earth: it's defined by convention.

Specifically, the direction of spin of a body relative to the celestial background is a vector found with the right hand rule (or cross-products). That vector is "celestial north". This actually matters a great deal if you want to do orbital mechanics calculations, because it also defines which direction is positive (which you need t get correct if you're trying to launch into orbit from a spinning body).

Here on Earth, you might have heard that magnetic north is slightly off from "true" north. The "true" north referenced there is the celestial pole.

There is also an orbital north, which is normal to the orbit instead of to the spin. That's convenient for some things, but less convenient for establishing a reference system on an object. Here, Lando was almost certainly referencing celestial north, not orbital north.