The spearhead of the project is Professor Annapurni Subramaniam. Photo: Pallava Bagla
Merak village, Ladakh:
The sun is the harbinger of life on Earth, yet we understand so little about our nearest star. The sun gets very angry sometimes; it then unleashes massive solar storms that down or burn up satellites and electronic equipment on Earth. To track the sun, India is trying to set up the National Large Solar Telescope (NLST) in Ladakh.
Spearheading the project is Professor Annapurni Subramaniam, director, Indian Institute of Astrophysics (IIA), Bengaluru, who says site characterization has taken place and land has been acquired. Only final approval is needed to get this massive and much-needed project off the ground. It’s almost a decade too late.
According to the IIA, the National Large Solar Telescope will be a two-meter-class optical and near-infrared (IR) observing facility. It is designed to address a range of important scientific issues related to the origin and dynamics of the Sun’s magnetic fields with a spatial resolution of 0.1-0.3 arcseconds.
The instrument has a broad scope to support and substantiate the multitude of solar-atmospheric observations from the space-based Aditya L1 satellite mission and the ground-based solar telescope at Udaipur in Rajasthan.
According to IIA, solar storms or Coronal Mass Ejections are large expulsions of billions of tons of plasma and associated magnetic fields from the Sun into interplanetary space, some of which can impact Earth and cause geomagnetic storms. Extreme geomagnetic storms have the potential to harm human life on Earth that depends on space technology, such as disrupting radio communications, GPS signals, etc. Predicting these storms is an important area of scientific research at IIA as well as many others institutions in India.
(Above) Dr. Ajay K Sood, Chief Scientific Advisor to the Government of India (second from right), visits the Merak site for the National Large Solar Telescope.
The telescope will be installed on the banks of Pangong Tso Lake in Merak, Ladakh, at an altitude of about 4,200 meters. Being a cold desert at high altitude, this location is best suited for optical and near-IR observations. The site offers significant periods of clear skies with high transparency. Laminar winds with mild gusts during the day provide periods of exceptional clarity.
The National Large Solar Telescope would be the ground counterpart of ISRO’s space-based solar observatory, the Aditya L-1 satellite.
Dr. Subramaniam said it is true that the satellite is already in orbit and delivering results while the NLST was delayed. She adds that if all goes well, approvals will happen very soon and the telescope could appear in a few years. The telescope project will cost over Rs 150 crore.
Placing the telescope on the banks of the huge Pangong Tso Lake has many advantages: the body of water provides a calmer atmosphere to make sharper observations and the persistent breeze will also help keep the instruments cool, as solar telescopes tend to move very quickly to warm up.
The Office of the Chief Scientific Advisor recently released a ‘Mega Science Vision – 2035’ document stating: “The NLST will be the largest solar telescope in the country. We recommend this as the highest priority project in solar astronomy.”
On July 6, 2024, India’s Chief Scientific Advisor Ajay K Sood visited the solar telescope site and took stock of developments. “The region is known for its exceptionally clear skies and low light pollution, making it an excellent location for stargazing.”