Hanle is one of the best optical observing sites on earth, and the reasons are geographic. It sits in the cold desert of Ladakh, high above most of the atmosphere, with very low humidity, minimal cloud cover and almost no artificial light for hundreds of kilometres. Those conditions are what allow a modestly sized 2-metre telescope to produce internationally competitive science. HCT's strength has been transient astronomy — supernovae and other events that flare and fade within days — where the decisive advantage is being able to point at a target within minutes of an alert. Remote operation from Bengaluru is central to that: astronomers do not have to travel to a 4,500-metre site to catch a transient, and the telescope is one of the earliest examples anywhere of routine remote observatory operation.

The telescope is named after Subrahmanyan Chandrasekhar, the Indian-American astrophysicist who won the Nobel Prize in Physics for his work on the structure and evolution of stars, and whose name is attached to the Chandrasekhar limit — the maximum mass of a stable white dwarf. The Hanle site has since grown into a wider astronomy cluster, and the region around it has been developed as a dark sky reserve to protect observing conditions from light pollution. The approved upgrade from 2 metres to a 3.7-metre segmented mirror, extending into the infrared, will substantially increase the light-gathering power available to Indian astronomers at the site.