From the March 1975 issue

Assembly of the ESO telescope

Construction of the 3.6 m telescope, in which CERN is collaborating with the European Southern Observatory (ESO), has now reached the important stage of testing. To check the rigidity of the telescope, which weighs more than 200 tonnes, and to finalise the control system, which will be fully automated, the telescope is being assembled in one of the halls of the Société Creusot-Loire at St. Chamond, France.

Tests will continue until April when the telescope will be dismantled and sent by sea to Chile, where assembly will start at the beginning of 1976. At the receiving end, on the La Silla mountain, work is well advanced on the building that will house it.

When the telescope comes into operation it will provide European astronomers with a first-class instrument for observing the comparatively unexplored Southern skies. Objects of particular interest are the central region of the Milky Way Galaxy and the Magellanic Clouds. The Clouds are outside the galaxy and can be seen only from the Southern Hemisphere. They contain old stars, young stars and stars in formation, and are thus a magnificent natural laboratory.

• Compiled from texts on pp71–72.

Events at CERN

(Figure 1) On 26 February, the Spiral Readers at CERN clocked up their millionth measured event on bubble chamber film. This type of semi-automatic measuring machine was initiated at Berkeley. Two have been built at CERN, the first coming into action for regular film measurement in 1970. They both now operate at a rate of about 70 vertices per hour.

(Figure 2) The last physical obstacle to the free passage of protons between the PS and SPS falls to the drill during the annual shutdown. The wall is in the beam transfer tunnel where protons are taken from the PS to the ISR.

At this point, protons will be bent off down a tunnel leading to the underground 400 GeV synchrotron ring.

• Compiled from text on p70.

Compiler’s Note

In 1962 five European governments set up ESO in the style and spirit of CERN, and by 1969 an observatory site had been procured at La Silla, 2400 m high in the Atacama desert, Chile. But the fledgling organisation was not only based on CERN, it was based at CERN prior to establishing its own headquarters in Garching, Germany, in 1980. And so, apart from the huge mirror, ESO’s 3.6 m optical telescope was built at CERN.

And the local link continues. A consortium, led by Michael Mayor from the Geneva University Observatory, built HARPS, a High Accuracy Radial Velocity Planet Searcher. Installed on the 3.6 m telescope in 2003, this spectrograph can detect “wobbles” smaller than 4 km/h in the radial velocity of a star, caused by the gravitational pull of orbiting planets. Such exceptional precision has revealed the existence of hundreds of extrasolar planets. Some of them, super-Earths, have masses of a few terrestrial masses, and some of these lie in the so-called Goldilocks zone of their host star, where life might be sustainable.

To survey the northern skies, HARPS-N was installed on the Italian 3.58 m Telescopio Nazionale Galileo at the Observatorio del Roque de los Muchachos, La Palma island, Canaries, in 2012.

Now those little green men (and women) have nowhere to hide.

About the author

Compiled by Peggie Rimmer