Monday, 6 August 2012

Triple-A: Aperture Arrays at ASTRON

There's a new weblog specifically for aperture arrays in radio astronomy, written by Ilse van Bemmel.

Although KAIRA has a much bigger scope that just astronomy, this new feature might well be of interest to many of our readers. We asked Ilse for an introduction, and this is what she sent us:

When you think about radio astronomy, most people imagine the fantastic big dishes that collect the radio emission from the farthest regions of the Universe. However, to see the faintest possible structures, a very large number of dishes is needed, and this rapidly becomes very expensive. A new technology to make very cheap and flexible radio telescopes is aperture arrays. These are in essence large collections of fairly simple and cheap receivers, which are combined with a computer to mimic a single large dish.
This technology was developed for radio astronomy at ASTRON over the last decades, and is now at a level at which it can be used to build radio telescopes. The first one of this kind is the LOFAR ( telescope, currently the world's largest radio observatory. However, LOFAR is still small compared to the ultimate goal: the Square Kilometre Array (SKA,
For low frequencies there is no doubt that aperture arrays are the best technology for the SKA. But for the 'classical' radio astronomy frequencies around 1GHz, aperture arrays have to compete with the well-known and well-understood dishes. Aperture arrays are cheaper, can look in multiple directions at once, can observe over enormous frequency ranges, and can be triggered to look at a particular source pretty much instantaneous. However, they are the new kid on the block, and processing the data into scientifically sensible images is still a challenge.
In this blog I describe my efforts at understanding how aperture arrays work from an astronomical perspective, and my attempts to engage fellow astronomers to embrace the technology (pun towards EMBRACE fully intended). Follow me through the circle which engages engineers ('do you have an exact number for it?'), discussions with fellow astronomers ('within an order of magnitude is fine...'), and the management ('there is currently no budget for that').

It's a great web log and is recommended to all who are interested in the progress being made in radio astronomical phased arrays.

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