MEMORIES of the collapse of one of the world’s biggest radio telescopes can
be laid to rest, now that finishing touches are being made to its successor.
Engineers have installed the last of 2004 aluminium panels on a new 110-metre
dish at Green Bank in West Virginia, where a 91-metre dish collapsed in
1988.
The National Radio Astronomy Observatory’s colossal new dish will give
unprecedented views of distant galaxies in the throes of their formation,
revealing the chemical make-up of dust and gas inside. It will be better at
gathering radio waves with wavelengths of around 3 millimetres than any other
telescope, thanks to a few technological tricks.
Most radio telescopes use several struts to suspend a receiver above the
centre the dish, but this blocks parts of the dish. The new Green Bank Telescope
is shaped in an unusual way so it can reflect radio waves to a receiver off to
one side. Motors will also move the panels on the dish’s surface, allowing it to
avoid distortion. “One big effect is the Sun coming up—it heats one side
of the dish and not the other,” says Tony Beasley of the NRAO. The official
opening is pencilled in for 25 August.
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