Astrophysicists detected pulsed gamma-ray emissions from the Crab pulsar with energies that exceed 100 billion electronvolts (GeV). A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The Whipple Observatory 10-metre reflector, operating a 37-pixel camera, was used to observe the Crab Nebula in TeV gamma rays. The paper announcing their finding was published on July 1 1989.

The Crab pulsar is a rapidly spinning neutron star that exploded in a supernova in the year 1054 to leave behind the Crab Nebula. The Nebula rotates at about 30 times a second and the pulsar has a co-rotating magnetic field from which it emits beams of radiation.

Read more: "Observation of TeV gamma rays from the Crab nebula using the atmospheric Cerenkov imaging technique" – Astrophysical Journal, Part 1, 342 (1989) 379-395