Galactic coordinate system. Positions of objects are measured in terms of their galactic longitude( l ) and galactic latitude ( b ). The galactic plane slices the Galaxy in half (top and bottom).
The galactic plane is tilted at an angle of 63 degrees to the celestial equator and at an angle of 60 degrees to the ecliptic (the path of the Sun on the sky). All three coordinate systems have poles which point in different directions on the sky.