The atmospheric conditions of the Maidanak Observatory in Uzbekistan for ground-based observations
Abstract
The site testing studies at the Maidanak Observatory in Uzbekistan for the period 1996-2007 are presented. Nightime seeing was measured with the ESO Differential Image Motion Monitor. The median zenith seeing (FWHM) value at 500 nm for the entire period of observations is 0.71 arcsec. A maximum clear sky season for Maidanak is July-September, with about 90% of possible clear time and a median seeing of 0.69 arcsec. The best monthly median seeing 0.62 arcsec observes in November. Negligible correlation between seeing and the wind velocity at ground level have been found. During an additional site testing campaign organized in July 1998, the median wavefront outer scale being 25.9 m and median isoplanatic angle being 2.48 arcsec were measured with the Generalized Seeing Monitor. This corresponds to a remarkably large atmospheric time constant. Simultaneous measurements of total seeing and microthermal measurements of surface layer optical turbulence were carried out in July-August 2002 which allowed us to estimate the surface layer contribution to the total seeing and which has been found to be about 8%.