More than a big house for a big telescope
European consortia are studying how to build a land-based telescope bigger – in a field where size counts – and more powerful than any Earth-bound star-gazing tool built to date. But an Extremely Large Telescope (ELT) of this kind needs a purpose-built enclosure to work within. For this, a Swedish-led team have just the right design, say the ELT project which recently announced the winner of its ‘telescope building' competition.
Preliminary design studies, carried out by the OWL and Euro50 projects, both funded by the EU's Sixth Framework Programme (FP6), are underway to build a bigger Earth-based telescope than anything currently on the planet. With this facility, astronomers hope to be able to probe deep space, to unravel some of cosmology's dark secrets – peering into dark energy and matter – and perhaps to trace the origins of the Universe.
One aspect of ELT's preparations is to come up with an enclosure for the large telescope – work being carried out by the Instituto De Astrofísica De Canarias (IAC) in Spain. IAC announced this month the winner of its ‘telescope building' design competition, with the top honour going to a proposal submitted by a team from Lund, Sweden called ‘E-BAT', short for European Bladed Advanced Telescope Enclosure.
A Spanish design was also commended by the selection jury which commented, in its deliberations, that “it was a pleasure to note that architectural aspects have been taken into account in many of the designs”.
“This is highly gratifying,” says Göran Sandberg, professor of structural mechanics at Lund Institute of Technology and project director for the Lund team's construction proposal. “Since this project is so unique, it requires entirely new solutions in terms of construction, which has made our work both stimulating and challenging.”
“The body of the enclosure is bisected by a combined observation and ventilation aperture,” Sandberg explains. One of the design's key features is a series of shutters or blades which are aerofoil-like and capable of different configurations – adjustable edge flaps, for example, can steer the wind and reduce turbulence in the air-stream entering the enclosure.
The telescope and its roughly 200-metre high building require advanced engineering, optics, and mathematical and IT solutions. The primary mirror of the planned telescope will be at least 50 metres across. Today's largest ground-based telescope, the Keck Telescope in Hawaii, is less than ten metres. The size of the mirror is crucial to the sharpness and resolution of the image.
“With the new telescope, the collection of light and focus will be ten thousand times better than today,” explains Arne Ardeberg, a professor of astronomy at Lund University who has long supported the idea of constructing a telescope in line with what the EU is now investigating. The Lund team's Euro50 project, together with another pan-European proposal, OWL, have been instrumental in the wider ELT mission. The telescope is planned to be located in northern Chile or in the Canary Islands – where good light is more or less guaranteed – but will not be operational for perhaps another decade.
The €7 000 being awarded to the Lund team for their enclosure design is a symbolic honour, says Sandberg. “The next step, of course, is to meet with the IAC people and come up with a plan for breathing more life into our design,” he told Headlines.Swedish Research Council and Lund University and Institute of Technology