The Combined Array for Research in Millimeter-wave Astronomy (CARMA) was an astronomical instrument comprising 23 radio telescopes, dedicated in 2006.

The high elevation site was chosen to minimize millimeter wave absorption and phase decoherence by atmospheric water vapor.

Pioneering work on compensating for the image distortion resulting from turbulent water vapor distributions in the troposphere started in the fall of 2008.

[citation needed] Over these distances the variation in the time of arrival of signals at the different telescopes as they pass through different amounts of water vapor severely limits the quality of images.

Observing CO is an indirect indicator of the presence of molecular hydrogen gas (the most abundant molecule in the universe) which is difficult to detect directly.