The galactic equator (or galactic plane) is an imaginary plane that slices the Galaxy in half (top and bottom). In the galactic coordinate system, the equator is at galactic latitude b = 0.
The galactic equator
is tilted at an angle
of 63 degrees to the celestial equator
. Since the ecliptic
, the path of the Sun
on the sky, is inclined at an angle
of 23.5 degrees to the celestial equator
, the galactic equator
are nearly at right angles (63 + 23.5 = 86.5 degrees), although this is purely coincidental.
A line passing through the observer perpendicular to the galactic equator
passes through the north galactic pole
(NGP) and south galactic pole
on the celestial sphere