Hanle in Changthang region of Ladakh is one of the most beautiful, enchanting and soul loosing places in India. It is the site of the 17th century Hanle Monastery (gompa) of the “Red Hat” Tibetan Drukpa Kagyu branch of Tibetan Buddhism and is located in the Hanle Valley on an old branch of the ancient Ladakh – Tibet trade route. The view from the top of the monastery are breath-taking. The valley is home to about a thousand people, with about 300 people living in Hanle village.
Sengge Namgyal died at Hanle on his return from an expedition against the Mongols who had occupied the Tibetan province of Tsang and were threatening Ladakh.
Indian Astronomical Observatory:
Hanle is also home to the Indian Astronomical Observatory (IAO). The location of both the village and the observatory are highly sensitive due to the close proximity of the Tibetan / Chinese border and special permission is needed to visit either by the Indian Government. Fukche airport is 24 km away, and Ukdungle town is close by. India has also set up a GRT (Gamma Ray Telescope), Himalayan Chandra Telescope, of 2 m diameter at Hanle. Once complete the Major Atmospheric Cerenkov Experiment Telescope gamma ray telescope being built here will be the world’s largest telescope at the highest altitude and the second largest gamma ray telescope in the world.
The Hanle site is deemed to be excellent for visible, infrared and submillimeter observations throughout the year. Specifically the observation conditions yield about 255 spectroscopic nights per year, approximately 190 photometric nights per year and an annual rain plus snow precipitation of less than 10 cm. In addition, there are low ambient temperatures, low humidity, low concentration of atmospheric aerosols, low atmospheric water vapour, dark nights and low pollution.
The Observatory has two active telescopes. These are the 2.01 meter optical-infrared Himalayan Chandra Telescope (HCT) and a High Altitude Gamma Ray Telescope (HAGAR). The HCT is remotely operated from Bangalore from the Centre for Research and Education in Science and Technology (CREST) using a dedicated satellite link.
Himalayan Chandra Telescope
The Himalayan Chandra Telescope is a 2.01 meters (6.5 feet) diameter optical-infrared telescope named after India-born Nobel laureate Subrahmanyam Chandrasekhar. It contains a modified Ritchey-Chretien system with a primary mirror made of ULE ceramic which is designed to withstand low temperatures it experiences. The telescope was manufactured by Electo-Optical System Technologies Inc. at Tucson, Arizona, USA. The telescope is mounted with 3 science instruments called Himalaya Faint Object Spectrograph (HFOSC), the near-IR imager and the optical CCD imager. The telescope is remotely operated via an INSAT-3B satellite link which allows operation even in sub-zero temperatures in winter.
High Altitude Gamma Ray Telescope
The High Altitude Gamma Ray Telescope (HAGAR) is an atmospheric Cerenkov experiment with 7 telescopes setup in 2008. Each telescope has 7 mirrors with a total area of 4.4 square meters. The telescopes are deployed on the periphery of a circle of radius 50 meters with one telescope at the center. Each telescope has alt-azimuth mounting.
Center for Research and Education in Science and Technology
The Center for Research and Education in Science and Technology (CREST) is situated 35 km to the northeast of Bangalore near Hoskote town. The Center houses the control room for the remote operations of the 2m Himalayan Chandra Telescope (HCT) at the Indian Astronomical Observatory, Hanle, and the HCT data archive. The operations are controlled using a remote satellite link.