Allen Telescope Array

The Allen Telescope Array (ATA) is a radio-telescope array of 42 6.1-meter dishes at the Hat Creek Radio Observatory (HCRO) in northern California, owned by the SETI Institute (an organization supporting SETI research, the search for extraterrestrial intelligence). It has a wide field of view and covers frequencies 0.5-11.2 GHz. In addition to SETI research, it is suitable for other radio astronomy applications including 21-cm line observations, and it has been used for and radio time-domain astronomy, including pulsar and magnetar study, as well as fast radio burst (FRB) discovery and study, the latter of both SETI and astrophysics interest. The 42 dishes (ATA-42) went operational in 2007, after which there have been some receiver upgrades.

From its beginning, it was planned to increase it in stages to 350 dishes (ATA-350), but as of 2025, I've found nothing to indicate that it has more than the original 42 or that such an upgrade is currently progressing in any manner. Significant expansion would require a substantial grant; The SETI Institute is privately funded and it has been a challenge simply to fund the ATA's operation, and funding beyond that has been used to update the existing configuration.