ATA: How It Works
The ATA is part of a new trend in radio astronomy. Rather than a single large dish, it is an array of a large number of small dishes (LNSD). Other countries (Australia, South Africa) are building LNSD arrays and an international consortium is planning a Square Kilometer Array that will use this new approach to radio telescope design.
Large single dishes are expensive, one-of-a kind development projects with every aspect optimized to get the best result for that investment. Once built, improving their performance is difficult and expensive. The ATA represents an entirely different approach, for it uses commercial technology wherever possible. The dish components are manufactured through a process developed for the commercial television market, and are relatively inexpensive. The sensitivity of the array is easily increased by simply adding more dishes, an approach that is clearly impractical for large, single-dish antennas. The ATA also takes advantage of receiver and cryogenic technologies originally developed for radio communication and cell phones. The instrument employs programmable chips and software for signal processing, which allows an increase in capability as new computer technology becomes available.
Over time, and with sufficient funding, the ATA will grow to 350 dishes. It will then have a collecting area equivalent to a single dish 114 meters in diameter, and the angular resolution of a dish 700 meters across. The ATA-350 will have point source sensitivity comparable to the National Radio Astronomy Observatory’s Robert C. Byrd Telescope and the Very Large Array, while being far faster and superior for imaging surveys.