The MAGIC Collaboration has built in 2002 / 2003 a first large atmospheric imaging Cherenkov telescope, MAGIC-I, with a mirror surface of 236 sq.m. and equipped with photomultiplier tubes of optimal efficiency. In 2009, a second telescope of essentially the same characteristics was added; MAGIC-II was installed at a distance of 85m from MAGIC-I. With the accent of these instruments on large mirror surface and best light collection, cosmic gamma-rays at an energy threshold lower than any existing or planned terrestrial gamma-ray telescope have become accessible. So far achieved has been a threshold of 25 GeV.
Located near the mountain top of the Roque de los Muchachos on the Canary island of La Palma, the construction of this world-wide largest telescope (MAGIC-I) was completed in 2003. Fully operational since 2004, it has been run ever since by an international collaboration of 17 institutes in 8 countries.
A second telescope, MAGIC-II, situated at the same site, was installed and commissioned in 2010. In large parts, MAGIC-II is a copy of the original MAGIC-I, but it has a more homogeneous camera with more pixels, and a refurbished readout. In 2012, in a major upgrading operation mostly concerning MAGIC-I, the two telescopes were made technically identical.
MAGIC-II is located at a distance of 85 m from the first MAGIC telescope. The stereo operation of both telescopes has increased the sensitivity of the observatory by a factor of ~3.
The MAGIC telescopes have observed the Crab pulsar at the highest energies yet achieved for this source, and the lowest for any IACT. The results strongly challenge current theories for the emission of gamma rays.
The MAGIC telescopes observed gamma rays above 50 GeV from the Crab pulsar, an inaccessible energy for most high energy instruments. Pulsed emission was detected at energies as high as 400 GeV. This is 50-100 times higher than predicted by current theoretical models. After the 2011 detection by MAGIC, VERITAS confirmed gamma rays above 100 GeV in 2012. After the full analysis of data collected, the MAGIC collaboration presented the most detailed and precise measurement of the periodic emission throughout the energy range of 50-400 GeV and showed that the duration of pulses is only one millisecond. The measurements by MAGIC, together with those of the orbiting Fermi satellite at much lower energies, provide an uninterrupted spectrum of the pulses from 0.1 GeV to 400 GeV. These clear observational results create major difficulties for most of the existing pulsar theories that predict significantly lower limits for highest energy emission.