The El Leoncito Astronomical Complex (CASLEO) is a prominent astronomical observatory located in the Calingasta department, west of the province of San Juan, Argentina. Inaugurated on September 12, 1986, it is situated 2,552 meters above sea level in an astronomical reserve of 70,000 hectares that ensures the preservation of the quality of its sky.
Every year, around 80 researchers and thesis students, both Argentine and foreign, participate in observation proposals using CASLEO's telescopes. Researchers from 33 countries, including Argentina, have been part of working teams that utilized the 2.15 m telescope during the decade of 2011-2020. Observations obtained at CASLEO have resulted in more than 60 university theses and over 1,200 scientific publications, with half of them in peer-reviewed international journals.
The complex offers both daytime and nighttime visits, allowing astronomy enthusiasts and the general public to enjoy guided observations of the sky. To visit CASLEO, it is recommended to make prior reservations, especially for nighttime observations. Its main instrument is the "Jorge Sahade" telescope, a 2.15-meter diameter Ritchey-Chrétien reflector, considered the largest in Argentina.
Located 1,263 kilometers from the City of Buenos Aires, a 15-hour drive is required to reach CASLEO, crossing seven states. The complex is part of the El Leoncito National Park, a protected area that offers the opportunity to explore natural trails and participate in astrotourism activities. About 30 kilometers south of Barreal, CASLEO is accessible via Route 149.
The combination of top-notch scientific facilities and a privileged natural environment makes the El Leoncito Astronomical Complex a must-visit destination for astronomy and nature lovers.
