In her budget speech on Sunday, Union Finance Minister Nirmala Sitharaman highlighted that the government has decided to fund the installation of the National Large Solar Telescope (NLST), and the National Large Optical-infrared Telescope (NLOT), and upgrade the Himalayan Chandra Telescope.
Further strengthening Ladakh’s reputation as the hub of astronomy in India, the government on Sunday announced the setting up of two new large telescopes, and upgradation of an existing one in the region. It also revealed its plan to establish a state-of-the-art planetarium in Andhra Pradesh, similar to the one built in Mysuru recently.
In her budget speech on Sunday, Union Finance Minister Nirmala Sitharaman highlighted that the government has decided to fund the installation of the National Large Solar Telescope (NLST), and the National Large Optical-infrared Telescope (NLOT), and upgrade the Himalayan Chandra Telescope.
Both the telescope facilities are slated to come up in Ladakh, which already has several operational sky observation facilities, including the Chandra telescope. The new telescopes will be operated by Bengaluru-based Indian Institute of Astrophysics (IIA), which runs the Indian Astronomical Observatory in Hanle valley of Ladakh where multiple telescopes are installed for facilitating different kinds of research.
The NLOT is supposed to be located in Hanle, while the NLST would be installed in Ladakh’s Merak region.
Dibyendu Nandi, a solar physicist at IISER Kolkata, said the decision was a big boost to the astronomy community in India.
“Getting observation time on international telescopes is extremely challenging because of the number of requests from groups all over the world. India’s decision to build these large telescope facilities will be a big benefit for Indian researchers,” Nandi said.
Ladakh, particularly its Hanle region, is already one of the biggest centres for astronomy research in the country, hosting dozens of big and small telescopes, including community telescopes. Located over 4,000 metres above sea level, the region has exceptionally dark skies, with very low light pollution which offers near-ideal conditions for making observations. It is also home to the Hanle Dark Sky Reserve, a first-of-its-kind protected area, meant to preserve the natural darkness of the night sky. There are also strict regulations on outdoor lighting in this area.
IIA director Annapurni Subramaniam said the astronomy community was delighted with the budget announcement.
“Ladakh is one of the world’s best locations for observational astronomy. This site, being high-altitude and cold desert, allows telescope operations round-the-year unlike many other locations in India where telescope operations are temporarily shut during the monsoon,” she said.
As such, having astronomy infrastructure and facilities up and running in Ladakh is both strategic and vital to obtain the maximum scientific output for science, she said.
The NLOT is expected to be built over the next one decade while the solar telescope (NLST) would take about 5 to 6 years to be installed.
Calling it a game-changer, solar physicist Dipankar Banerjee said, “There are solar observatories in Hawaii and Europe but a large observatory was missing in this part of the world. NLST will fill that gap and offer solar observations which have never been taken before.”
In 2023, India had launched its first space-based solar observatory, Aditya L1.
“NLST operating from the ground will complement Aditya L1 in space,” Banerjee, Vice Chancellor, Indian Institute of Space Science and Technology, noted.
NLST, which is proposed to be built near the banks of Pangong Tso Lake in Merak, will be one the largest solar telescopes in Asia. This 2-metre class telescope will allow the study of the Sun in much finer detail. The NLST comes with a spatial resolution of 50 km and a time resolution of 1 millisecond.
“There are few observatories dedicated to the study of the Sun and the NLST will complement and contribute to maintaining the continuous observations of the Sun. It offers to study the finer events and turbulent occurrences originating from the Sun, which are otherwise impossible with small aperture telescopes or even the space-based observatories,” Nandi said.
The NLOT is a unique optical-infrared 10-metre class telescope facility. It will be established in the Indian Astronomical Observatory in Hanle. Its design is based on the segmented mirror technology, which is very close to the proposed Thirty Metre Telescope (TMT), an international facility which has India as a collaborator.
The NLOT will enable studies of the early universe, its origins, development of planetary systems and their morphological formations, exoplanets and more.
“When ready, NLOT will fill the existing longitudinal gap. Our efforts in developing TMT will come handy for NLOT,” said senior astrophysicist GC Anupama, adding that the astronomy community had been working on these telescope ideas for over a decade.
The Himalayan Chandra Telescope has been operational in Hanle since 2001. Science observations obtained using this facility were first released in 2003. It has three onboard instruments and is remotely operated by the IIA’s facility in Hoskote, located in the outskirts of Bengaluru. This facility is now slated to undergo a major upgrade in its infrastructure and operational facilities.
“Astronomical data from Hanle is crucial, and HCT has been providing it continuously. This upgrade will happen over the next few years,” noted Subramaniam.
The budget also mentioned a second Cosmology Education and Research Training Center (COSMOS) planetarium, which will come up in Andhra Pradesh’s Amravati. It is a next-generation planetarium, soon to be inaugurated in Mysuru and is being spearheaded by the IIA. It will promote astronomy education, public astronomy outreach communication.