IC 10
It was discovered in 1887. Edwin Hubble suspected it might belong to the Local Group of galaxies, but this was uncertain for decades. The radial velocity of IC 10 was measured in 1962. It is approaching the Milky Way at about 350 km/s. This strengthened the evidence for its being in the Local Group. Its membership in the group was finally confirmed in 1996 by measurements of its distance by observations of Cepheids. Despite its closeness, the galaxy is rather difficult to study because it lies near the galactic plane of the Milky Way. It is heavily obscured by interstellar matter.