Membership of the European Southern Observatory grew to 10 last week with the accession of the United Kingdom. Founded in 1962 with just five European countries, the UK now joins a consortium comprising Belgium, Denmark, France, Germany, Italy, the Netherlands, Portugal, Sweden, and Switzerland.

Today the ESO operates from two sites in the Atacama Desert in Chile. The original observatory, La Silla, is the largest in the Southern Hemisphere and is home to several optical telescopes up to 3.6 meters in diameter and a 15-m submillimetre radio telescope. But there?s no doubt that the new site at Paranal hosts the jewel in ESO?s crown. The Very Large Telescope (VLT) is so new that it hasn?t yet been used to its full potential. VLT?s four 8.2-m unit telescopes will mostly operate separately, but they can also be used together in interferometry mode (so far this has been demonstrated with two of the units), giving the telescopes enough power to see an astronaut on the moon.

Philip Best, a Royal Society University Research Fellow based at the Royal Observatory Edinburgh, welcomes the UK?s involvement with ESO. Prior to moving to Edinburgh 2 years ago, Best spent 3 1/2 years in the Netherlands where he had ready access to ESO data. He still has collaborators back in Leiden, so it has been possible for him to continue to get small amounts of time on ESO telescopes. But in general things have become increasingly difficult for astronomers in Britain over the last 5 years, he says. The reason? In this game, size matters.

Working at ESO

If you want to work at one of ESO?s sites in Chile, or its headquarters in Garching, Germany, make sure your qualifications are top notch. The "rule of preference" which favours scientists from ESO member countries only applies where applicants are inseparable on the basis of all other measures, says Director-General Catherine Cesarsky.

The ESO has openings for approximately five postdoctoral fellows every year, according to Bruno Leibundgut, head of the Office for Science. The fellowships last for 3 years if based in Germany. If the fellow works in Chile, however, he or she gets a fourth year which they can choose to spend with the ESO in Chile or Germany, or at a university in Chile or in any of the ESO?s 10 member states. Although fellows all work independently on a project they propose in their application, they also "all have a mentor from within the ESO staff," explains Leibundgut.

Like regular ESO staff, fellows have to commit a certain amount of their time to carrying out functional work on behalf of ESO and the wider astronomy community. In Germany this means that a quarter of their time is spent on instrumentation development, whilst in Chile 50% of a fellow?s time is functional work, including "80 nights on the mountain."

There is no bar on former fellows applying for permanent posts with ESO and, in fact, this is a regular occurrence according to Leibundgut. Staff posts are basically of two types. Research astronomers carry out functional duties for half their time and their own research for the other half. Research scientists have a much greater functional role, with only 20% of their time earmarked for research. What both groups have in common is "no privileges when it comes to observatory time"--they have to compete with astronomers from across Europe on the strength of their research proposals.

Best explains that today?s world-leading research is done almost exclusively on 8-m telescopes. In the last year, collaboration with the U.S., Canada, and a number of other, smaller partners has provided British astronomers with access to a quarter share in one of the pair of 8-m Gemini telescopes. But joining ESO effectively gives them full-time use of one of the VLT?s units. Where once the UK tried to go it alone, or in partnership with just one or two other countries, the need for "bigger and better instruments" means that "it must be right for countries to share in the collective development of facilities," according to Britain?s Minister for Science Lord Sainsbury. And Gerry Gilmore of Cambridge University, the UK?s member of ESO Council, admits that it was the VLT that really influenced the UK?s decision to join. "Five or 10 years ago, ESO was not technologically at the forefront," he says, but now British astronomers have realised, "these guys are good, we?d better get on board."

Indeed, according to Gilmore, ESO?s superb facilities mean that young astronomers in Europe are in an "overwhelmingly better position than the average graduate student in the United States," where those at rich, private universities are extremely well provided for, but everyone else is rather left out in the cold.

But doesn?t UK membership mean that astronomers in the nine existing member countries will lose out on telescope time? Catherine Cesarsky, ESO?s director-general, is quick to assert that British astronomers are more than welcome in the club. With facilities of the level of the VLT, she points out, it is possible to "make great discoveries in a few nights." Astronomers can then spend a great deal of time working on those few nights? data. And what is really important, because "we want to be the top observatory," is the pooling of European forces and the "strengthening of the community" which Britain?s membership brings, she says.

What?s more, although the rest of Europe?s astronomers may be one VLT unit down, the UK?s ? 124.6 million joining fee and ? 18.7 million annual dues mean that the future of another project, ALMA, is assured. The Atacama Millimetre Array, a joint ESO/U.S. project, will link 64 submillimetre antennas to allow observations down to wavelengths of 0.3 millimeters of a sensitivity and accuracy "comparable to what can be obtained at other wavelengths," explains Cesarsky. This will allow astronomers to study the earliest galaxies and the formation process of starts and planets.

And ESO is already making plans for an even more ambitious project. The 100-m diameter Overwhelmingly Large Telescope ( OWL) will be a ground-based optical/infrared telescope to outclass Hubble. The idea, explains Cesarsky, is to enable astronomers to "study the faraway universe as if it were very close," and to search for habitable planets.

Meanwhile, it?s not just the telescopes that are getting bigger. With formal negotiations under way with Finland, and several more countries interested in joining, ESO itself looks set to continue to expand.