Abstract

Abstract The site selection for the Iranian National Observatory (INO) was concluded in 2007. As a result of a 7-year campaign, Mount Gargash was identi ed to host INO observing facilities. For the purpose of atmospheric seeing measurement, an Automated Di erential Image Motion Monitoring (automatic DIMM) system has been installed few 100 meters to the mainpeak. Together with a weather station, this automatic DIMM system enabled us to continuously gather data on the main atmospheric features of the site namely seeing, temperature, wind speed and direction, and humidity, in an automated fashion. Here we present three years of automatic DIMM seeing measurement analysis of this INO site. The measurements indicate that the site bene ts from a low atmospheric seeing with median 0.6 arcsec and 1st and 3rd quartile being equal to 0.4 and 0.8 arcsec, respectively. We study the e ect of the target position on the seeing measurements with the purpose of optimizing our target selection criteria. Using the data, combined with the simultaneous weather data, we investigate the long-term pattern of the variation of the seeing and the meteorological parameters to help us understand the nature of the variations in the seeing and how it is a ected by the general meteorological conditions. These analyses helps us to improve the observing strategies during long and short term time-scales.