Catalog of Circumpolar Stars

The Catalog of Circumpolar Stars is a publication of a list of northern stars, assembled by Stephen Groombridge during the first third of the 1800s.

Circumpolar stars are stars that never fall below the horizon, i.e., never set as does the Sun and Moon. These are stars toward the nearer pole, e.g., the north pole if you are in the northern hemisphere. Exactly which stars are circumpolar depends upon the latitude from which you are observing: the further poleward you are, the larger the region of the celestial sphere has this quality: from the north or south pole you can see half the sky, and none of the stars set. From the equator, you can see the whole sky, but the stars set daily. Groombridge was observing roughly from London, where nearly the northern-most 40% of the celestial sphere is circumpolar.