The Llano del Hato National Astronomical Observatory (Spanish: OAN de Llano del Hato, or Observatorio Astronómico Nacional de Llano del Hato) is an astronomical observatory in Venezuela (IAU code 303). It is 3600 meters above sea level and is the country's main observatory. It is situated above the village of Llano del Hato in the Venezuelan Andes, not far from Apartaderos which lies about 50 kilometers north-east of Mérida, Mérida State.
This facility is the closest major optical observatory to the equator lying at 8 degrees and 47.51 minutes north. It therefore has access to most parts of both the northern and southern skies. It benefits from a very dark site, and its altitude of 3,600 meters (12,000 feet) above sea level means atmospheric turbulence is greatly reduced.
The observatory is under the auspices of the Centro de Investigaciones de Astronomia (CIDA), the main astronomical research body in Venezuela. CIDA conducts many projects in collaboration with other research organizations, academic institutions and international bodies. It also conducts valuable research in its own right and has a record that includes several important discoveries.
There are four large optical telescopes, each in its own cupola or dome: an 1-m Askania Schmidt camera (one of the largest telescopes of this type in the world), a 65-cm Zeiss refractor, a 1-m Zeiss reflector and a 50-cm Askania double astrograph. These instruments were acquired by the Venezuelan government 1954 and installed at Llano del Hato in the early 1970s. The observatory also has a museum and exhibition centre where visitors can learn about the work of the observatory and CIDA as well as astronomy in general.
The Quasar Equatorial Survey Team (QUEST) project is a joint venture between Yale University, Indiana University, and CIDA to photographically survey the sky. It now uses the 48 inch (1.22-m) aperture Samuel Oschin telescope at the Palomar Observatory with a digital camera, an array of 112 charge-coupled devices. Previously, it used the 1.0-metre Schmidt telescope of the Llano del Hato National Astronomical Observatory.