The Next Generation Radio Telescope
A BRIEF OVERVIEW
By Bob Dixon
In 1998, a new type of radio telescope is being designed based on a small
prototype designed and tested in 1992. This new telescope would operate as
a "Radio Camera", since it would form an image of the entire
sky at once.
Former Chief Engineer Jim Bolinger wrote his master's thesis on designing
and operating the prototype, an array of eight antennas that operated at
162 MHz and which successfully "located" weather station transmitters in
the region around Columbus OH. It achieved a resolution five times greater
than its "classical" resolution through the application of the CLEAN
Former Chief Engineer Jim Bolinger wrote his master's thesis on designing and operating the prototype, an array of eight antennas that operated at 162 MHz and which successfully "located" weather station transmitters in the region around Columbus OH. It achieved a resolution five times greater than its "classical" resolution through the application of the CLEAN computer algorithm.
|Artist's Conception of Argus Antenna Elements and Array
Plans are now in progress to design
and build a much larger array of dozens or hundreds of antennas. Chief
Engineer Steve Brown has written his masters thesis on several aspects of
this development, and several members of the Observatory are participating
in initial planning and design. We have named this the Argus telescope, after
the being of Greek mythology that had one hundred eyes and could see in
all directions at once. It is the physical realization of a
concept that has been fictionalized earlier by Carl Sagan in
his 1985 book, CONTACT, and by Arthur C. Clarke in his 1976
novel, IMPERIAL EARTH. An Argus array, searching for intelligent signals,
also made an "appearance" in the "Star Trek, The Next Generation" television
series. Since our initial concept of Argus, several other groups also
happened to use the name "Argus" for their search-oriented programs and
instruments, but these are independent efforts.
One concept for Argus is a spiral-like array of conically-shaped helical antenna elements. Each element would have a computer, and all the elements would be connected in a high-speed digital network. The small antennas would be placed along the spiral arms, spaced at logarithmically further intervals. They would operate over a range of 500 to 1000 MHz. Additional computers would combine and process the signals from each of the elements in such a way as to create simultaneous beams, looking in every direction of the sky at once. As these computations require great speed, the Argus concept depended on further development of inexpensive, high speed processors and data networks. As these are now available, the time is ripe to develop Argus.
An Argus array is ultimately less expensive than a larger single telescope, since its elements can be mass produced, it has no large or moving parts, and is unaffected by gravity or wind. The construction cost of a big dish increases with time and with size, while the cost of an array decreases with time as technology improves performance and lowers component costs. One fully-implemented Argus array can simutaneously carry out all the observations now being done by other comparable radiotelescopes, not only for astronomy but for all scientific and commercial monitoring of the electromagnetic environment. Examples of observational subjects include pulsars, aircraft, and spacecraft; as well as new and unexpected phenomena such as supernovae, gamma-ray bursts with radio artifacts, and of course potential SETI sources.
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