The Degree Angular Scale Interferometer (DASI) is a device created to study the Cosmic Microwave Background (CMB) anisotropies. It is a 13-element interferometer that operates on low frequency end of the microwave spectrum. In 2002, the DASI project scientist, John Carlstrom, announced that the Degree angular Scale interferometer (DASI) had successfully measured the polarization of the CMB.

The CMB measurements can reveal, with accurate precision, how the universe was like hundreds of years ago. The results of the experiment support the inflation theory of the origin of the universe. This theory proposes that the universe rapidly grew in mere fractions of a second immediately after the Big Bang.

The whole operation took place in Amundsen–Scott South Pole Station in Antarctica with the University of Chicago heading the experiment. The reason why this particular place was chosen was due to the low water vapor content of the atmosphere which could otherwise, cause severe contamination. The scientists heading the operation had to stay in Antarctica throughout the harsh winter season in order to measure the cosmic microwave background radiation. The Degree angular Scale interferometer (DASI) has an angular resolution around the one-degree scale and uses cooled high electron mobility transistor amplifiers.