The Hispanic Astronomical Center in Andalusia (CAHA), also known as the Calar Alto Observatory, is the largest astronomical observatory in the European continent, located in Calar Alto, a plateau 2168 m high in the Sierra de Filabres, in the province of Almería, Spain.
Founded in 1973 following an agreement between the German and Spanish governments, the observatory has five telescopes with different apertures and optical systems, with the 3.5 m telescope being the largest telescope on the European continent. The observatory is jointly operated by the Institute of Astrophysics of Andalusia - CSIC and the Andalusian Government since 2019 and conducts cutting-edge scientific research in various fields of astronomy, such as the search for exoplanets, star formation, galactic structure, and cosmology.

the largest observatory within continental Europe, you have to follow the instructions detailed in the Call for Proposals page.

At the 2.2m and 3.5m telescopes there are two possibilities to perform the observations: visitor and service mode. In visitor mode you must be at the observatory and will be assisted by the CAHA staff for the control of the telescope and instrumentation. In service mode, the observatory staff will perform the observations for you. In this case you must previously indicate all the relevant details concerning the instrumental setup and observing strategy required to carry out your proposal. You can find all the available instrumental possibilities on the instrumentation page.