World's Highest Gamma Ray Telescope In Ladakh: Why It Is A Big Deal

Major Atmospheric Cherenkov Experiment (MACE) is the highest of its kind in the world

Asia’s largest imaging Cherenkov telescope, located at an altitude of almost 4,300 metres, was inaugurated on Wednesday at Ladakh’s Hanle.

The Major Atmospheric Cherenkov Experiment (MACE) observatory, the highest of its kind of telescope in the world, has been indigenously built by the Mumbai-based Bhabha Atomic Research Centre (BARC) with support from the Electronics Corporation of India Ltd (ECIL) and other Indian industry partners.

The MACE observatory is touted to place India at the forefront of cosmic ray research globally by allowing scientists to study high-energy gamma rays. This will pave the way for deeper understanding of the universe’s most energetic events, such as supernovae, black holes, and gamma-ray bursts.

Even before its formal inauguration, the telescope produced high-quality work detecting gamma ray flares as far away as 200 million light years away.

About MACE observatory

MACE is 21 metres in diameter, 175 tonnes heavy, has reflector area of 356 sqm and 1,424 diamond-turned metallic mirror facets, 712 actuators, 1,088 photo-multiplier tubes, and 68 camera modules.

It is a lightweight construction and features high strength and temperature endurance. Reflector surface measuring over 350 square metres (sqm) comprises highly reflective diamond-turned custom-built metallic mirror facets that are required to be aligned with an accuracy of 2 mm over parabolic surface. The camera at the focal point contains a number of photomultiplier tubes mounted with specialised assembly to enhance light collection efficiency.

Ultrafast backend electronics with nanosecond digitization electronics is optimised for low-power and -temperature operations. Extreme weather conditions restrict transport to six-eight months a year and affect the availability of trained personnel on site.

How will the telescope work?

Gamma rays do not reach the Earth’s surface as they are stopped by the atmosphere. However, interaction with the atmosphere creates high-energy particles that travel faster than the speed of flight and emit Cherenkov radiation which is akin to a sonic boom. The mirrors and cameras capture these flashes and trace them back to its cosmic source.

Why Hanle?

The site has been carefully chosen for its unique scientific advantages as Hanle offers extremely low light pollution required for gamma ray observations. The longitudinal advantage of its location enables MACE to observe sources invisible to other parts of the world.

“Hanle is like heaven for gamma ray astronomers with its dark skies, low humidity and almost no air pollution,” said Dr AK Mohanty, chairman, Atomic Energy Commission and India’s nuclear chief. He said another few more gamma ray telescopes could be built here, making Hanle the go-to place for global astronomers, some with international collaboration.