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 (including the SETI Institute and UC Berkeley) is planning a Square Kilometer Array.
Large single dishes are expensive, one-of-a kind development projects with every aspect optimized to get the best result for that investment. Once it is built, improving its performance is difficult and expensive. The ATA represents an entirely different approach. We use commercial technology wherever possible. The dish components are manufactured through a process developed for the television industry. Thus, the dishes are relatively inexpensive. We can increase the sensitivity of the array by simply adding more dishes. Increasing the collecting area of a large single dish is possible but is difficult and expensive. The receivers and cryogenic refrigerators were developed for radio communication and cell phones. We use programmable chips and software for signal processing. This allows us to increase the capability of the ATA as new computer technology becomes available.
Over time, with sufficient funding, the ATA will grow to 350 dishes. It will then have the 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 sensitivity comparable to the National Radio Astronomy Observatory’s Robert C. Byrd Telescope and Very Large Array, with survey and imaging capabilities complementing both.