The Observatorio Astrofísico de Javalambre (OAJ) is a scientific facility located at the Sierra de Javalambre in Teruel, Spain, particularly conceived and constructed by the Centro de Estudios de Física del Cosmos de Aragón (CEFCA) for carrying out large sky astronomical surveys. The OAJ mainly consists of two professional telescopes with large fields of view (FoV) and seeing-limited image quality all over their entire FoVs: the 2.5m Javalambre Survey Telescope, JST250, a large-etendue telescope with a FoV of 3 deg diameter, and the 80cm Javalambre Auxiliary Survey Telescope, JAST80, with a FoV of 2deg.
Both telescopes are equipped with panoramic cameras, state-of-the-art, large format CCDs and unique sets of optical filters suited to survey the Universe in an unprecedented way all over the optical spectral range.

The OAJ Project started in 2010, comprising not only the design and construcción of the two above telescopes but of the whole civil work, related installations and infrastructures for the proper operation of the telescopes. This includes, among others, a seeing DIMM monitor, a 40cm telescope for robotic determination of the optical extinction curve, an all-sky extinction camera, a residence, three control rooms, laboratories and workshops, a data center, an AIV clean room, a coating vacuum chamber for mirror alluminization (the latter to be ready by end 2015), and all the general installations for the running of the observatory. It all is connected by underground tunnels. In 2014, the OAJ was finalized and declared Spanish ICTS (Instalación Científico-Técnica Singular) by the Spanish Ministry of Economy and Competitiveness.

The OAJ is managed and operated by CEFCA, a foundation of public interest of the Departamento de Industria e Innovación of the Government of Aragón that was created in 2008 to define and construct the OAJ, as well as to carry out and promote its scientific exploitation. In this sense, J-PLUS and J-PAS are the two first key surveys that are defined to be conducted at the OAJ in the period 2015-2022. The CEFCA data center, UPAD, with capacity for 6.1 PB of storage, 3.3 TB of RAM and 406 cores, complete the OAJ Project at the city of Teruel, allowing to process and storage the data gathered with the above surveys.