[1][2] At the end of the 1980s, a search for the of quality sites for astronomical observation in the Iberian Peninsula identified, among others, the Sierra de Javalambre as a candidate.

Due to the lack of funds to ensure a minimum infrastructure that would allow work to continue during the following winter and spring, the measurements were interrupted.

However, the data that could be accumulated in the short period of observations were not sufficient to draw statistically valid conclusions and the survey could only point to the potential of the site, but not confirm it.

This measurement would be made from a photometric mapping of about 8,000 square degrees with narrow filters, which could provide redshift values with the required accuracy and for a sufficient number of sources.

A two-fold process then began to carry out both the systematic characterization of the quality of the chosen site and the concept study of the proposed telescope.

[3] In parallel, a study on cloud cover was commissioned using high-resolution satellite images of the Pico del Buitre area for the years 2005 and 2006.

[3] In the second half of 2007, 5 companies were contacted to carry out a conceptual study for a large-field, ~2m aperture telescope with high image quality over the entire field.

A person in charge of the project was proposed with the task of preparing a report to be evaluated by internationally recognized experts.

The tender process chosen was that of competitive dialogue, which in the Public Sector Contracts Law is considered particularly appropriate for the supply of sophisticated scientific equipment.

The contract was signed on March 22, 2010 with the joint venture formed by the companies AMOS and Torrescámara, the former being responsible for the construction of the telescopes.

[5] The OAJ mainly consists of two professional wide field of view (FoV) telescopes with good image quality throughout the field: Both telescopes are equipped with state-of-the-art panoramic cameras with large format CCDs and a unique set of optical filters specially designed to map the Universe across the entire optical spectrum range unprecedented in international astrophysics.