The Washington system - Photometric properties and standard stars

Observations on the Washington Photometric System (C,M,T1,T2), leading to an expanded set of 79 standards, are presented. This primary standard list extends to a V magnitude of approximately 12.0. A V filter has been added to the system, which permits V-T1 colors and V magnitudes on the Johnson system. Revised primary and secondary extinction values from four observatories are presented. The extent of errors in the standard colors is discussed. Reddening effects are also discussed.