  We report on the Iranian National Observatory (INO) ongoing site
characterization studies for INO 3.4m optical telescope under development. Iran
benefits from high altitude mountains and a relatively dry climate, thus offer
many suitable sites for optical observations. The site selection (2001-2007)
studies resulted in two promising sites in central Iran, one of which will host
the 3.4m telescope. The studies between 2008 and 2010 aimed at detail
characterization of the two sites. This involved measurements of a number of
parameters including the wind speed and wind direction, astronomical seeing,
sky brightness and microthermal variations.
