THE HESS II telescope (High Energy Stereoscopic System), started operating in Namibia last week. The telescope observes the most violent and extreme phenomena of the universe.

The HESS II telescope with its 28-metre mirror is the largest Cherenkov telescope ever built. It has a mass of 600 tons and take up an area of about two tennis courts.

Together with the four smaller 12-metre telescopes already in operation since 2004, the HESS Observatory outside Windhoek will continue to define the forefront of ground-based gamma ray astronomy and will allow deeper understanding of known high-energy cosmic sources such as supermassive black holes, pulsars and supernovae and the search for new classes of high-energy cosmic sources.

"This new telescope not only provides the largest mirror area among instruments of this type worldwide, but also resolves the cascade images at unprecedented detail, with four times more pixels per sky area compared to the smaller telescopes," said Pascal Vincent of the French team responsible for the photo sensor package of the mirror.

The telescope structure and its drive system were designed by engineers in Germany and South Africa, and produced in Namibia and Germany. The 875 hexagonal mirror facets which make up the huge reflector were manufactured in Armenia, and individually characterised in Germany. The mirror alignment system results from cooperation between German and Polish institutes. The camera, with its integrated electronics, was designed in France.

The construction of the new telescope was driven and financed by German and French institutions, with significant contributions from Austria, Poland, South Africa and Sweden.

The HESS II camera, with an area of the size of a garage door and weight of almost three tons, is 36 metres above the primary mirror in the focal plane at a hight of a 20-storey building when pointing up.

The HESS Observatory has been in operation for almost a decade now with the collaboration of more than 170 scientists from 32 scientific institutions and 12 different countries. To date, this collaboration has published over 100 articles in scientific journals.

In a survey in 2006 HESS was ranked the 10th most influential observatory worldwide, joining the ranks with the Hubble Space telescope and the telescopes of the European Southern Observatory (ESO) in Chile.