The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California. The MWO is located on Mount Wilson, a 5,715 foot (1,742 m) peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles.Thanks to the inversion layer that traps smog over Los Angeles, Mount Wilson has naturally steadier air than any other location in North America, making it ideal for astronomy and in particular for interferometry.The growth of greater Los Angeles has limited the ability of the observatory to engage in deep space astronomy, but it remains a productive center with many new and old instruments in use for astronomical research.