If we use the galactic coordinate system to locate objects within the Galaxy, we can identify the galactic anti-centre as the point where the galactic longitude ( l ) = 180 degrees and the galactic latitude ( b ) = 0 degrees.

The galactic coordinate system. Positions of objects are measured in terms of their galactic longitude ( l ) and galactic latitude ( b ). The galactic equator slices the galaxy in half (top and bottom).