Consider the following statements about recently inaugurated Asia’s largest and world’s highest imaging Cherenkov Observatory, at Hanle, Ladakh : I. It was inaugurated by Ajit Kumar Mohanty, Chairman, Atomic Energy Commission. II. It is located at an altitude of 5100 metres. III. The telescope is built by Bhabha Atomic Research Centre with the support of Electronic Corporation of India and other industry partners. Choose the correct answer from the options given below :

Correct — option (3), Only I and III are correct.

The Department of Atomic Energy's release on PIB, dated 8 October 2024, settles each statement.

Statement I is correct. The Major Atmospheric Cherenkov Experiment (MACE) Observatory was inaugurated at Hanle on 4 October 2024 by Dr. Ajit Kumar Mohanty, Secretary DAE and Chairman of the Atomic Energy Commission.

Statement II is incorrect. MACE is located at an altitude of about 4,300 m, not 5,100 m. At that height it is the highest imaging Cherenkov telescope in the world.

Statement III is correct. The telescope was indigenously built by the Bhabha Atomic Research Centre (BARC) with support from ECIL, the Electronics Corporation of India Limited, and other Indian industry partners.

I and III true, II false: the code is Only I and III are correct.

The idea to remember: MACE at Hanle is at about 4,300 m, built by BARC with ECIL, inaugurated on 4 October 2024.

Why the others are wrong

• (1)
  Only I and II are correct. — Statement I is right, but Statement II is not. The DAE release puts MACE at an altitude of about 4,300 m, some 800 m below the 5,100 m in the statement.

  This code also leaves out Statement III, which is correct: BARC built the telescope with support from ECIL and other Indian industry partners.

• (2)
  I, II and III are correct. — This code accepts all three statements, including the wrong one. MACE stands at about 4,300 m, so Statement II's 5,100 m fails.

  Statements I and III do hold: Dr. Ajit Kumar Mohanty inaugurated MACE on 4 October 2024, and BARC built it with support from ECIL and other industry partners.

• (4)
  Only II and III are correct. — This code rejects a correct statement and accepts a wrong one.

  Statement I is correct: the release says Dr. Ajit Kumar Mohanty, Secretary DAE and Chairman of the Atomic Energy Commission, inaugurated MACE at Hanle on 4 October 2024. Statement II is wrong, because the altitude is about 4,300 m, not 5,100 m.

When a very high-energy gamma ray from space hits the upper atmosphere, it sets off a cascade of charged particles called an air shower. These particles move faster than light travels in air, and so give off a faint, very brief flash of bluish light: Cherenkov radiation.

An imaging Cherenkov telescope collects that flash with a large mirror and records the shower's image with a fast camera. From the image, astronomers work out the direction and energy of the original gamma ray.

The effect is named after Pavel Cherenkov, who shared the 1958 Nobel Prize in Physics for the discovery and interpretation of the effect.

Key facts

• MACE Observatory at Hanle, Ladakh, was inaugurated on 4 October 2024 by Dr. Ajit Kumar Mohanty, Secretary DAE and Chairman, Atomic Energy Commission.
• MACE stands at an altitude of about 4,300 m, the highest imaging Cherenkov telescope in the world.
• MACE is the largest imaging Cherenkov telescope in Asia.
• BARC built MACE indigenously, with support from ECIL and other Indian industry partners.
• MACE observes high-energy gamma rays, to study events such as supernovae, black holes and gamma-ray bursts.

Common traps

• Accepting an altitude that merely sounds right for Ladakh. MACE is at about 4,300 m; 5,100 m is wrong.
• Doubting Statement I because the inaugurating official is a scientist-administrator rather than a minister. DAE's release names Dr. Ajit Kumar Mohanty, Secretary DAE and Chairman AEC.
• Rejecting Statement III over the wording 'Electronic Corporation of India'. The release credits ECIL, Electronics Corporation of India Limited, alongside BARC.

UnlockIAS compared this question with questions from other RAS Prelims papers and found none similar enough to link.

• practice — not a real PYQ

  The MACE telescope inaugurated at Hanle, Ladakh, in October 2024 is designed to observe:

  • (a)Radio waves from pulsars
  • (b)High-energy gamma rays
  • (c)Infrared radiation from exoplanets
  • (d)Neutrinos from the Sun
  Answer(2) — DAE says MACE will observe high-energy gamma rays. As an imaging Cherenkov telescope, it does so through the Cherenkov light their air showers produce. Options (1), (3) and (4) are other kinds of signals, which are not what DAE describes MACE observing.
• practice — not a real PYQ

  Which organisation indigenously built the MACE telescope at Hanle, with support from ECIL and other Indian industry partners?

  • (a)Indian Space Research Organisation
  • (b)Bhabha Atomic Research Centre
  • (c)Physical Research Laboratory
  • (d)National Physical Laboratory
  Answer(2) — The DAE release says the telescope was indigenously built by BARC with support from ECIL and other Indian industry partners. Options (1), (3) and (4) are other national science organisations, not named as MACE's builder.