Excerpt from Stargazer by Fred Watson, plus links to reviews, author biography & more

It has to be said that it was not so much the directors and project managers of the new facilities who were responsible for fostering this view. Nor was it the organisers of the symposium. But aperture fever stalked the corridors and halls of the International Congress Centre like a prowling tiger, and voices could be heard urging radical cuts in the funding of telescopes that had until recently been among the world's largest.

The organisers of the symposium had clearly attempted to defuse the issue through the way they had programmed the meetings. Their view was that there is still so much to be learned about the Universe, both near and far, that every telescope pointing to the sky has a valid and useful part to play. As long as the funding can stretch that far, they should all be utilised. And what made that view so evident was the prominence they had given to the symposium's other major attraction—the presentations on auxiliary instrumentation.

The field of astronomical instrumentation is one that rewards clever and innovative thinking without incurring the enormous costs of new telescopes. Typically, it involves dazzling technology of the kind used in adaptive optics. But it extends far beyond that limited area. For example, imagine a spectrograph that can compensate for poor atmospheric conditions by allowing not one but hundreds of objects to be observed at a time. It would allow a 4-metre class telescope on an indifferent site to explore novel and quite unique niches of astronomical research. That is exactly the approach that had been taken during the 1990s with the 3.9 metre Anglo-Australian Telescope at Siding Spring Observatory, one of the oldest of the 4-metre class machines, dating from 1974.

Innovative instrumentation can revitalise old-fashioned telescopes and transform them into giants of astronomical productivity. It is the real equaliser in the balance of telescope superiority—and the true antidote of aperture fever. 'Power Telescopes and Instrumentation into the New Millennium' boasted no fewer than 160 presentations on auxiliary instruments for ground-based telescopes, and another 100 on adaptive optics. One might have thought that this kind of prominence would have averted an aperture fever epidemic altogether.

And indeed, it almost did.



Starving the fever

Half a world away, on a mountain peak in Chile called Cerro Paranal, the world's biggest optical telescope was in its final stages of assembly. This giant instrument, being built by the European Southern Observatory, incorporated four separate 8-metre class telescopes that could be used independently or linked together to mimic a single 16 metre dish. Three of them were already in operation. For all the linguistic elegance of the European partnership that had given it life, it sported a very ordinary name. It was, and remains, the VLT—the Very Large Telescope.

Even as the VLT was being built, there was talk of still larger telescopes. At the last European conference on optical telescopes, four years earlier, a handful of proposals for amazing instruments with much larger mirrors had been presented. One had been called the ELT—the Extremely Large Telescope—and the name had stuck as a generic term for a new telescope class: ones with mirrors 25 metres in diameter. Mirrors for these giants would not be made from single slabs of glass but from assemblies of smaller pieces under computer control—the now-proven segmented-mirror technology.

The thinking that had raised eyebrows in 1996 had become commonplace by 2000—'from wild to mild', as one participant put it. It had brought with it a whole new vocabulary of telescope names. For example, Caltech offered CELT (the California Extremely Large Telescope), while a Swedish university consortium championed SELT (the Swedish Extremely Large Telescope—which has since been renamed Euro50). On the other hand, the somewhat pretentious MAXAT (the Maximum Aperture Telescope) was about to be discarded in favour of the GSMT (the Giant Segmented-Mirror Telescope) by its own enthusiastic proponents. Enthusiasm notwithstanding, none of these proposals had got remotely near the construction stage and only CELT had any real prospect of being funded in the near future.

From Stargazer by Fred Watson, pages viii - x of the Prologue, and pages 1-17 of Chapter 1. Copyright Fred Watson. All rights reserved. Excerpt reproduced by permission of Da Capo Press.