Furthermore, inhomogeneities in the water vapor distribution cause variations in the electrical path length through the atmosphere. These variations result in phase errors that degrade the sensitivity and resolution of images made with both interferometers and filled aperture telescopes. Radiometric properties of the atmosphere opacity stability Physical structure of the atmosphere meteorology stratification turbulence Physical characteristics of the site topology geology Installed equipment Moonrise over NRAO test equipment near Cerro Chajnantor, Chile. A 20 foot ocean shipping container provides operations base and shelter for personnel and instruments. Solar power system.
Electrical power is supplied by a battery bank and array of solar panels.
The 225 GHz tipping radiometer is the benchmark instrument for site characterization. It measures the atmospheric absorption every 10 minutes and atmospheric emission stability every fifth hour. Operation is automatic. Sporadic repair is required. The data are retrieved daily by telephone and summaries are posted monthly.