Super-bright galaxies powered by black holes have helped astronomers come up with the most accurate distance yet to the iconic Pleiades star cluster.
The measurement, which used quasars as bright and consistent relative-distance markers, charted the famous "Seven Sisters" star cluster at 136.2 parsecs, or 444 light-years, away from Earth.
The Sagittarius Window Eclipsing Extrasolar Planet Search, or SWEEPS, was a 2006 astronomical survey project using the Hubble Space Telescope's Advanced Camera for Surveys - Wide Field Channel to monitor 180,000 stars for seven days to detect extrasolar planets via the transit method.
The stars that were monitored in this astronomical survey were all located in the Sagittarius-I Window, a rare transparent view to the Milky Way's central bulge stars in the Sagittarius constellation as our view to most of the galaxy's central stars is blocked by lanes of dust. These stars in the galaxy's central bulge region are approximately 27,000 light years from Earth.