25 Years of the Himalayan Chandra Telescope: India Celebrates a Milestone in Astronomy

Why is it in the news?

India has celebrated 25 years of successful operations of the 2-metre Himalayan Chandra Telescope (HCT) at Hanle, Ladakh. A three-day conference organized by the Indian Institute of Astrophysics (IIA) highlighted the telescope's achievements, scientific contributions, and future expansion plans.

About the Himalayan Chandra Telescope (HCT)

• The Himalayan Chandra Telescope (HCT) is a 2-metre optical telescope located at Hanle, Ladakh, at an altitude of 4,517 metres. 
• It is operated by the Indian Institute of Astrophysics (IIA), an autonomous institute under the Department of Science and Technology (DST). 
• The telescope was named after Nobel Laureate Subrahmanyan Chandrasekhar. 
• HCT achieved its First Light on 26 September 2000 and was dedicated to the nation in August 2001. 

Why was Hanle chosen?

Hanle is one of the best astronomical sites in the world because of:

• Over 250 clear observing nights every year. 
• Very low atmospheric water vapour, ideal for infrared observations. 
• Highly transparent skies. 
• Minimal light pollution. 
• High altitude and dry climate. 

Unique Feature

• Since June 2001, the telescope has been operated remotely in real time from the IIA campus in Hosakote, Bengaluru. 
• It uses a dedicated INSAT-3B satellite link provided by ISRO, making it one of India's earliest remotely operated telescopes. 

Scientific Contributions

Over the past 25 years, HCT has made significant contributions in astronomy, including:

• Study of gamma-ray bursts. 
• Research on supernovae and novae. 
• Discovery and study of exoplanets, including participation in the discovery of TRAPPIST-1b. 
• Spectroscopy of comets. 
• Studies of stars, nebulae, galaxies, quasars, and active galactic nuclei (AGN). 
• Long-term monitoring of young stars and variable stars. 

Current Instruments

The HCT is equipped with:

• HFOSC – Optical camera and spectrograph. 
• uTIRSPEC – Near-infrared spectrometer and imager. 
• HESP – High-resolution Echelle spectrograph. 

Future Plans

• The Union Budget has announced:
• 3.7-metre Upgraded Himalayan Chandra Telescope (UHCT). 
• 13.7-metre National Large Optical-Infrared Telescope (NLOT) at Hanle. 
• These projects will be led by the Indian Institute of Astrophysics (IIA) and are expected to significantly strengthen India's astronomical research capabilities.

Hanle: India's Astronomy Hub

Today, Hanle hosts several major astronomical facilities, including:

• Himalayan Chandra Telescope (HCT) 
• GROWTH-India Telescope 
• MACE (Major Atmospheric Cherenkov Experiment) Telescope 
• HAGAR (High Altitude Gamma Ray) Telescope 
• Hanle Dark Sky Reserve, established to preserve the region's exceptionally dark skies. 

Significance

The Himalayan Chandra Telescope has played a key role in advancing optical and infrared astronomy in India. Its success has established Hanle as a globally recognized astronomical site and laid the foundation for India's next generation of world-class telescopes.

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