The European Southern Observatory Catalog is an astronomical catalog that contains a log of observations performed with the ESO telescopes at La Silla and Paranal observatories, including the APEX submillimeter telescope on Llano de Chajnantor, as well as the UKIDSS/WFCAM data obtained at the UK Infrared Telescope facility in Hawaii. The observations themselves normally have a proprietary period of one year.[1] After this period the archival data sets can be requested by users worldwide.[2]