The Allen Telescope Array (ATA) is a “Large Number of Small Dishes” (LNSD) array designed to be highly effective for simultaneous surveys undertaken for SETI projects (Search for Extraterrestrial Intelligence) at centimeter wavelengths.
The initiative for building the ATA emerged from a series of workshops convened by the SETI Institute beginning in 1997. These workshops were charged with defining a path for future development of SETI technologies and search strategies. The relentless advance of computer and communications technologies made it clear that LNSD arrays were more efficient and less expensive than the large antennas traditionally constructed for radio astronomy and SETI. The final report of the workshop, “SETI 2020,” recommended the construction of a so-called One Hectare Telescope, having a collecting area commensurate with its name.
The SETI Institute sought private funds for such an instrument, and in 2001 Paul Allen (co-founder of Microsoft) agreed to fund the technology development and first phase of implementation, culminating in the construction of 42 antennas. In October 2007 the array began commissioning tests and initial observations.