Wednesday, June 18, 2008

A telescope that spans over four continents



Astronomers have set up a radio telescope which spans over four continents, a feat they claim is the first in the world.

Scientists have long combined observations from individual telescopes through interferometry, a process that produces the same resolution as a single dish as wide as the distance between the antennas.

Now, an international team, led by Arecibo Observatory in Puerto Rico, has developed the integrated telescope.

Its size gives it ten times the resolution of the Hubble Space Telescope, allowing the array to image objects, like the bright 'afterglow' formed when a high-speed jet of matter from a gamma-ray burst slams into its surroundings, that just look like points to individual radio telescopes

In an observational run, it was found that antennas in North America, South America, Europe and Africa all pointed in the same direction. Signals were fed by fibre optics in a bid to create real-time images at a hub in the Netherlands.

Previously, data from each telescope was recorded on discs and mailed to a central location. Now, data is sent via fibre optic cables to produce real-time images of celestial objects

For the astronomers, the telescope will allow them to plan follow-up observations for rapidly changing phenomena, such as supernovae.

Such observing plans, which can change quickly depending on what the target does, were hard to justify when the data was still in the mail. These are very expensive telescopes. They don't just give away time on the off-chance that something will happen

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