The Degree Angular Scale Interferometer (DASI) was a telescope installed at the U.S. National Science Foundation's Amundsen-Scott South Pole Station in Antarctica. It was a 13-element interferometer operating between 26 and 36 GHz in ten bands. The instrument is similar in design to the Cosmic Background Imager and the Very Small Array. In 2002 the DASI team reported the first detection of polarization anisotropies in the Cosmic Microwave Background.
In 2010, the DASI mount was repurposed for the Keck Array, which also measures CMB polarization anisotropy.
Coordinates: 90°00′S 139°16′W / 90.000°S 139.267°W