![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/%25C3%2584quatorium_01.jpg/640px-%25C3%2584quatorium_01.jpg&w=640&q=50)
Equatorium
Astronomical calculating instrument / From Wikipedia, the free encyclopedia
For the region of South Sudan, see Equatoria.
An equatorium (plural, equatoria) is an astronomical calculating instrument. It can be used for finding the positions of the Moon, Sun, and planets without arithmetic operations, using a geometrical model to represent the position of a given celestial body.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/%C3%84quatorium_01.jpg/640px-%C3%84quatorium_01.jpg)