Supergalactic coordinate system - a simple definition

For studies of more distant extragalactic objects, the most natural coordinate system is supergalactic coordinate system. The reference plane of this system is defined by Gerard de Vaucouleurs as the plane where density of galaxies in our environment is the largest.

Supergalactic longitude, SGL, is measured counterclockwise from direction l = 137.37 deg, b = 0 deg. The values are between 0 and 360 degrees in decimal format (degrees).

Supergalactic latitude, SGB, is measured from the supergalactic plane, positive northwards and negative southwards. The values are between -90 and +90 degrees in decimal format (degrees).