All Sky Automated Survey

The All Sky Automated Survey (ASAS) was a Polish photometric survey begun in 1997 to monitor transients. It began in the late 1990s with a telescope at the Las Campanas Observatory (LCO), Chile, which was upgraded in the early 2000s to a configuration of multiple telescopes, and an additional telescope was added on Haleakala, Maui in 2006. It viewed roughly twenty million stars down to magnitude 14, including 50,000 variables over the southern 3/4 of the sky with 39,000 credited as discoveries. Circa 2013-2014 it was replaced by All Sky Automated Survey for SuperNovae (ASAS-SN), which has better sensitivity for identifying distant supernovae.