Astronomers at the National Radio Astronomy Observatory (NRAO) have found the distance to the Pleiades star cluster, also known as the Seven Sisters. This was done to resolve the controversy regarding the Pleiades' distance, which was measured wrongly by a cosmic-mapping research satellite, Hipparcos of European Agency. Hipparcos, which was launched in 1989 to precisely measure the positions and distances of thousands of stars, produced a distance measurement of only about 390 light-years.
The NRAO astronomers studied the Pleiades in the constellation Taurus, easily seen in the winter sky. This relatively nearby cluster contains hundreds of young, hot stars formed only about 100 million years ago.