In line with the envisioned role of the INO observatory to become an international scientific platform for astronomy, it will host a number of observing facilities. The principal telescope, the INO340, 3.4-m diameter Ritchey‐Chrétien optical telescope offering a field of view of 20 arcmin at the main Cassegrain focus with an image resolution of better than 0.5 arcsec (FWHM) across the field. Three side ports are available, each offering an 8-arcmin field of view, thus the telescope backend can be simultaneously equipped with up to four instruments. The working wavelength range of the telescope is 325-2,500 nm, though the initial focus will be on the optical range. The observatory is also host to a multi-lens array called the INOLA which will be used to study ultra-low surface brightness systems at visible wavelengths. In addition, there is a site monitoring station which is comprised of three elements; a seeing monitor (Auto DIMM), an all sky camera and a weather station.
Support facilities near the summit, include a central control room, a coating and service building, a site monitoring station and an observer’s residence down the hill close to the city of Qamu. The telescope dome is 16 m in diameter and benefits from an active cooling system both inside the dome and in a lower floor to prevent thermal leak from human activities or equipment. The service building consists of a mirror cleaning/coating hall and a central control room.
The observatory site is under construction after an eight-year selection campaign, which led to the choice of the Mount Gargash Peak, at an altitude of 3,600 m. Site selection was followed by equally exhaustive site characterization and monitoring activities. The civil construction – being, the telescope pier, the enclosure building and the service building – began in 2017. The 11.5-km access road has been operational since 2016. The site is suitably located at 51° E, bridging the hour angle gap between the modern astronomical observatories of eastern Asia and east Atlantic. With a median seeing of ~0.6 arcsec the location is one of the most promising sites for astronomical observations in the Northern Hemisphere.