The latest on Hanle Dark Sky Reserve (HDSR) is that it recently hosted its third annual Star Party from September 18 to 23, 2025.

• This event brought together astronomy enthusiasts, astrophotographers, scientists, and local communities for four nights of stargazing under some of the darkest skies in India. The Star Party was organized by the Indian Institute of Astrophysics (IIA), the Department of Wildlife Protection of UT Ladakh, and the Bhabha Atomic Research Centre (BARC).
• HDSR, notified in December 2022, is India’s first International Dark Sky Reserve, centered around the Indian Astronomical Observatory at Hanle village of Ladakh.
• It is located in the Changthang Wildlife Sanctuary at around 4,250-4,500 meters altitude and offers Bortle-1 skies, the darkest sky category globally.

Location and environment

• Altitude: The reserve is situated approximately 4,500 meters above sea level in the Changthang Wildlife Sanctuary.
• Climate: As a cold, high-altitude desert region, Ladakh offers a large, arid area with consistently clear, cloudless, and dry skies, which are ideal for astronomical observation.
• Pristine skies: Due to minimal artificial light pollution, Hanle has some of the darkest skies in India, ranking as the country's largest Bortle-1 region. This allows for naked-eye viewing of celestial phenomena like the Milky Way and the Zodiacal Light. 

Astronomy and research

Indian Astronomical Observatory: Hanle is home to the IAO, operated by the Indian Institute of Astrophysics (IIA). This facility houses one of the world's highest optical telescopes.

• Research: The IAO uses its telescopes to study stars, galaxies, exoplanets, and the evolution of the universe.
• Sky protection: The IAO has led efforts to preserve the region's dark skies to ensure the continuation of its valuable astronomical research. 

Astro-tourism and community engagement

• Astro-ambassadors: A key feature of the HDSR is its community-centric model. The local administration and the IIA have trained and equipped 24 young villagers, two-thirds of whom are women, to be "Astronomy Ambassadors".
• Guided experiences: The ambassadors use 8-inch telescopes to guide tourists through the wonders of the cosmos, providing stargazing shows for a fee.
• Economic development: This astro-tourism initiative creates new income streams for the local population and promotes science-based socio-economic development in the region.
• Annual events: The HDSR hosts an annual "Star Party" that brings together professional and amateur astronomers from across the country. 

Protecting the dark sky

To preserve the exceptional night sky quality, a comprehensive Light Management Plan is in place. 

• Minimizing light pollution: The plan provides households with equipment like thick curtains and light shades to reduce light trespass.
• Traffic regulations: Vehicles within the reserve are asked to use dim headlights.
• Visitor guidelines: Tourists are advised to use red-filtered lights, dispose of waste properly, and avoid loud noises to maintain the environment's integrity.

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