COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 576 Konkoly Observatory Budapest 1971 August 24 HD 101799, A COMPLETELY ECLIPSING W UMa SYSTEM The eclipsing character of HD 101799 was discovered by Bond (1970) on Curtiss-Schmidt prism-objective plates and confirmed by y-photoelectric observations. We report in this Note the first results of 1350 U, B, and V observations secured at Cerro Tololo Inter-American Observatory. They were made with the 16 inches (No 1) Observatory's telescope through a UBV set of standard filters and an RCA 1P21 photomultiplier refrigerated in a thermoelectric cold box. The variable star was observed differentially in relation to the comparison star HD 101834. The observations show the system to be a W UMa star with stationary light within the minima, i.e., the system undergoes total eclipses. Figure 1 displays the V-observations obtained on April 16, 1971. We derived eleven times of minimum for each light curve in U, B, and V. They arc listed in Table I; the residuals (O-C) and cycles are from the linear least squares ephemeris: P.M. - JD hel. 2441060.12322 + 0.37022894d . E +-12 +-25 including the first time of minimum computed from the y-observations kindly supplied by Dr. Bond. The light curve analysis will be further published. [FIGURE 1] Table I: Times of minimum of HD 101799. ------------------------------------------------------ Min.Color JD. hel W Cycles O-C 2440000+ ------------------------------------------------------ II V 0648.98393 2 -1110.5 -0.00005d II V 1056.60640 2 -9.5 +0.0004 B .60633 2 -9.5 +0.0003 U .60652 1 -9.5 +0.0005 I V 1057.53220 2 -7.0 +0.0006 B .53191 2 -7.0 +0.0003 U .53144 1 -7.0 -0.0002 II V 1057.71742 2 -6.5 +0.0007 B .71732 2 -6.5 +0.0006 U .71749 1 -6.5 +0.0008 I V 1058.64279 2 -4.0 +0.0005 B .64242 2 -4.0 +0.0001 U .64353 1 -4.0 +0.0012 II V 1059.56809 2 -1.5 +0.0002 B .56798 2 -1.5 +0.0001 U .56740 1 -1.5 -0.0005 I V 1059.75328 2 -1.0 +0.0003 B .75350 2 -1.0 +0.0005 U .75370 1 -1.0 +0.0007 I V 1060.49285 2 +1.0 -0.0006 B .49273 2 +1.0 -0.0007 U .49292 1 +1.0 -0.0005 II V 1060.67834 2 +1.5 -0.0002 B .67877 2 +1.5 +0.0002 U .67820 1 +1.5 -0.0004 I V 1061.60395 2 +4.0 -0.0002 B .60383 2 +4.0 -0.0003 U .60298 1 +4.0 -0.0012 II V 1063.63973 2 +9.5 -0.0007 B .63972 2 +9.5 -0.0007 U .63958 1 +9.5 -0.0008 I V 1064.56504 2 +12.0 -0.0009 B .56545 2 +12.0 -0.0005 U .56676 1 +12.0 -0.0008 ------------------------------------------------------ August, 1971, Observatorio Astronomico and R.F. SISTERO I.M.A.F., CORDOBA, ARGENTINA M.E. CASTORE DE SISTERO Reference Bond, H.E. 1970, Pub.A.S.P., 82, 1065. [BIBCODE 1970PASP...82.1065B ]