Félix Aguilar Observatory (Spanish: Observatorio Félix Aguilar, or Observatorio Astronómico Félix Aguilar - OAFA) is an astronomical observatory in the San Juan Province of Argentina. Its primary observing facility is located El Leoncito National Park in the west of San Juan Province. Also located in El Leoncito Park is the Leoncito Astronomical Complex. The remote site was known as "El Leoncito Observatory" until 1990, when it became Carlos Ulrrico Cesco Astronomical Station (Spanish: Estación Astronómica Carlos Ulrrico Cesco - EACUC). The observatory is operated by the School of Physical and Natural Sciences at National University of San Juan in San Juan, Argentina.