= Differential Microwave Radiometer
{c}
= COBE DMR
{c}
{synonym}
= DMR
{c}
{synonym}
The <Differential Microwave Radiometer> measured differences in microwave power between pairs of sky directions to map <Cosmic microwave background anisotropy>. Comparing two directions suppresses a common absolute brightness offset; repeated comparisons during scanning are then combined into a sky map.
The COBE instrument used paired horn <antennas> at three frequencies, with independent channels that tested detector noise and frequency-dependent <galactic foreground> contamination. A differencing instrument does not by itself determine the absolute monopole <temperature>. Its measurement therefore complements the <spectrum> measured by the <Far Infrared Absolute Spectrophotometer>.<Structure in the COBE Differential Microwave Radiometer First-Year Maps by George F. Smoot and others>[Instrument design and differential-map construction]{ref}
Back to article page
