The Large Quasar Astrometric Catalog (LQAC): principle and construction .

International audienceThe huge and increasing number of quasars detected and identified from various sky surveys leads to a large quantity of data which brings various and inhomogeneous information concerning celestial coordinates with respect to the ICRF, photometry, spectroscopic and radio properties. The aim of the LQAC (Large Quasar Astrometric Catalog) is to compile all the recorded quasars until the present date, gathering the information above, when available, with the best estimation of their celestial coordinates with respect to the ICRF