Supergalactic coordinate system

As viewed from Earth, the plane traces a great circle across the sky through the following constellations: In the 1950s the astronomer Gérard de Vaucouleurs recognized the existence of a flattened “local supercluster” from the Shapley-Ames Catalog in the environment of the Milky Way.

Vera Rubin had also identified the supergalactic plane in the 1950s, but her data remained unpublished.

[1] The plane delineated by various galaxies defined in 1976 the equator of the supergalactic coordinate system de Vaucouleurs developed.

In years thereafter with more observation data available de Vaucouleurs' and Rubin's findings about the existence of the plane proved right.

The transformation from a triple of Cartesian supergalactic coordinates to a triple of galactic coordinates is The left column in this matrix is the image of the origin of the supergalactic system in the galactic system, the right column in this matrix is the image of the north pole of the supergalactic coordinates in the galactic system, and the middle column is the cross product (to complete the right-handed coordinate system).