What Happened
- The Union Budget 2026-27 approved two new major telescope facilities in Ladakh — the National Large Solar Telescope (NLST) and the National Large Optical-Near Infrared Telescope (NLOT).
- The existing Himalayan Chandra Telescope (HCT), which has completed 25 years of operation, will receive its first major upgrade.
- Both new facilities and the upgraded HCT will be operated by the Indian Institute of Astrophysics (IIA), Bengaluru, at the Indian Astronomical Observatory (IAO), Hanle, Ladakh.
- The NLOT will have a 13.7-metre segmented primary mirror consisting of 90 hexagonal segments, making it one of the largest optical-infrared telescopes globally, with operations expected by around 2030.
- The NLST will be installed at Merak, near Pangong Tso, and will observe the Sun's surface and atmosphere at high resolution; it is expected to be operational within 5-6 years.
Static Topic Bridges
Indian Astronomical Observatory (IAO) and Hanle Dark Sky Reserve
The Indian Astronomical Observatory at Hanle, Ladakh, sits at an altitude of 4,500 metres above mean sea level and is operated by the Indian Institute of Astrophysics (IIA), Bengaluru. Hanle is renowned for its exceptional observational conditions — approximately 255 spectroscopic nights and 190 photometric nights per year, with annual precipitation of less than 10 cm. In September 2022, the area around Hanle became India's first Dark Sky Reserve, covering 1,073 sq km within the Changthang Wildlife Sanctuary. The reserve enforces strict light-pollution controls and runs an astro-tourism programme, training local villagers as Astronomy Ambassadors.
- Altitude: 4,500 m above mean sea level (one of the highest astronomical observatories in the world)
- Managed by: Indian Institute of Astrophysics (IIA), Bengaluru, under Department of Science & Technology
- India's first Dark Sky Reserve declared in 2022
- Site classification: Bortle "Black" (darkest possible category)
- Hanle also hosts the High Altitude Gamma Ray (HAGAR) telescope array and the Major Atmospheric Cherenkov Experiment (MACE)
Connection to this news: The NLOT and NLST are being built in the same Hanle-Merak corridor, building on existing IAO infrastructure and taking advantage of the dark sky and dry atmospheric conditions that make Ladakh India's premier ground-based astronomy site.
Types of Telescopes and Electromagnetic Spectrum
Telescopes are broadly classified by the wavelength of radiation they observe: optical (visible light), radio, infrared, ultraviolet, X-ray, and gamma-ray. Ground-based telescopes are limited to wavelengths that pass through the atmosphere (visible and radio windows), while space-based observatories like ASTROSAT (India's first multi-wavelength space observatory, launched 2015) observe across multiple bands from ultraviolet to X-ray. Segmented mirror technology, as used in the NLOT, assembles multiple smaller hexagonal mirrors into one large collecting surface, allowing construction of telescopes far larger than would be possible with a single primary mirror.
- NLOT: 13.7 m segmented mirror, optical-near infrared range; 90 hexagonal segments
- NLST: Solar telescope, high-resolution study of the Sun's photosphere and chromosphere
- HCT upgrade: Will receive a 3.7 m segmented primary mirror
- India's space astronomy mission: ASTROSAT (launched 2015 by ISRO) — multi-wavelength space observatory
- Comparison: World's largest optical telescope is the Extremely Large Telescope (ELT) under construction in Chile (39 m mirror)
Connection to this news: NLOT fills a critical gap in India's ground-based astronomy capability at optical-infrared wavelengths, complementing ASTROSAT's space-based observations and enabling India to participate in time-domain astronomy and exoplanet research at international standards.
India's Science & Technology Policy and Budget Allocations
Under the National Science, Technology and Innovation Policy (STIP 2020), India aims to double its research output and R&D spending (currently ~0.7% of GDP, target 2%). Major astronomy projects are funded through the Department of Science & Technology (DST) and the Department of Space. The Budget 2026-27 signals a continued commitment to frontier science infrastructure, alongside other announced projects like quantum computing missions and AI centres of excellence.
- Nodal ministry: Department of Science & Technology (DST)
- IIA: An autonomous institute under DST; established 1971
- India's other major telescope infrastructure: Giant Metrewave Radio Telescope (GMRT) near Pune; ASTROSAT (space)
- NLOT will be among the top five largest optical telescopes in the world when completed
- Solar observation context: India is also developing Aditya-L1, its first dedicated solar mission (launched 2023)
Connection to this news: The simultaneous announcement of NLST (solar) and NLOT (deep sky) demonstrates a two-pronged expansion of India's astronomical infrastructure — studying both the nearest star and the distant universe — consistent with STIP 2020 goals.
Key Facts & Data
- NLOT primary mirror: 13.7 m (90 segmented hexagonal mirrors), location: Hanle, Ladakh
- NLST: Solar high-resolution telescope, location: Merak (near Pangong Tso), Ladakh
- HCT: 2 m optical telescope, operational since 2000, first major upgrade now approved
- Hanle altitude: 4,500 m above mean sea level
- IAO operated by IIA, Bengaluru (under DST)
- India's first Dark Sky Reserve: Hanle (declared September 2022), area: 1,073 sq km
- NLOT expected operational: ~2030
- GMRT (Pune) — India's major radio telescope, upgraded to uGMRT in 2017
- ASTROSAT (2015) — India's first dedicated multi-wavelength space observatory
- Aditya-L1 (2023) — India's first dedicated solar observation mission in space