UBV photoelectric observations of stars in the Standard Areas of Landolt (1973,1983) during the period March 1991 - May 1992 have permitted to study the photoelectric system of the cassegrain reflector at Estación Astronómica "Dr.Carlos Ulrrico Cesco" and compare the obtained values and the original ones. The result obtained is excellent and the residues are very small, including in the (U-B).Asociación Argentina de Astronomí
