The model, in the low vertical-resolution mode used for forecasting, provides an estimate for the integrated vertical turbulence, converted to a fwhm of a star image. Mauna Kea does not have a DIMM, and plans by IfA to install one have not been assigned much priority. We will provide a DIMM similar to the portable DIMMs we have assembled for use in Chile, this will also allow direct comparison between possible Chile sites for the NBT and Mauna Kea for this parameter. This is inappropriate for an extensive site-testing campaign, and so we will investigate whether it is possible to construct a simple portable system that does not require use of an existing facility. Such an instrument would also be of great value to any existing AO system, over and above our use as a site characterization tool.
Radio frequency sounding can probe to a height of several km.
All telescope optics will need to be placed above this layer. Knowledge of the outer scale of turbulence, and its range of variation, is a critical parameter in the design of an active and adaptive optics system. Site Test equipment Equipment purchase began in CY1999. Three stand-alone weather stations with wind, humidity, solar flux and temperature sensors have been assembled and are presently being calibrated and tested. Three portable DIMMs, based on that developed by ESO, with software from U. Washington, are about to undergo testing on Cerro Tololo.