Microthermal tower, USNO and Columbia domes on Cerro Tololo

The 30-meter microthermal tower rises above the United States Naval Observatory (USNO) and Columbia domes on Cerro Tololo. More than fifty probes were simultaneously mounted at ten altitudes on the tower to measure microthermal variations, and thus seeing. The turbulence structure of the atmosphere is being tested with a SODAR acoustic profiler and Multi-Aperture Scintillation Sensor (MASS) units. The 6.5-meter tower to the right of the 30-meter is the Differential Image Motion Monitor (DIMM) tower for the Advanced Technology Solar Telescope (ATST) study. The tubular tower next to the USNO dome contains the DIMM2 Seeing Monitor. This is all part of a site testing campaign by the Thirty Meter Telescope sites group, as detailed in the September 2004 NOAO Newsletter (currently only available in PDF format).