COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 745 Konkoly Observatory Budapest 1972 December 12 "Rosemary Hill Observatory, Department of Physics and Astronomy, University of Florida, Gainesville, Florida Contribution No. 34." NOTES ON BV1481=AA CETI The variable star BV1481 (1950.0: alpha=1h54m40.6s, delta=23d9'44.9"), now named AA Ceti (Kukarkin et al., IBVS Nr. 717), was discovered to be a variable on Bamberg patrol plates (IBVS Nr. 586), and a set of light elements were calculated from times of faint light derived from these plates (IBVS Nr. 587). Extensive photoelectric observations with the 30" reflecting telescope at the University of Florida's Rosemary Hill Observatory have shown these elements to be incorrect. A new period has been found based upon five times of minimum in each color determined by the Hertzsprung method, five estimated times of minimum from partial coverage of only one branch of an eclipse, and the best times of faint light determined from the Bamberg plates (1964-1969). These data and the weights applied in a linear least squares calculation are shown in Table 1. The resulting elements and probable errors are: Min I = JD(hel.) 24412.68.6869 = 0.53617353d.E +-.0007 +-.00000050 The observed minus the calculated times of mid-eclipse are also given in Table 1 and are displayed graphically in Figure 1. Over 250 observations in each color (UBV) have been made on 14 nights all tending to support the fact that these elements are correct. The light curve shows continuous variation between eclipses and the secondary eclipse is total. Table 1 --------------------------------------------------------------------- Julian Date (hel.) E Weight O-C --------------------------------------------------------------------- 2438728.319 -4738.0 2 +0.022 38995.594 -4239.5 1 +0.015 39006.549 -4219.0 1 -0.022 39060.417 -4118.5 1 -0.039 39383.507 -3516.0 1 +0.006 39404.394 -3477.0 2 -0.018 39444.359 -3402.5 1 +0.003 39761.491 -2811.0 2 -0.012 39768.483 -2798.0 1 +0.010 39771.463 -2792.5 1 +0.041 40530.392 -1377.0 1 +0.016 40566.285 -1310.0 2 -0.015 41261.7176 - 13.0 5 +0.0010 .7176 - 13.0 5 +0.0010 .7155 - 13.0 5 -0.0011 41264.6665 - 7.5 4 +0.0009 .6687 - 7.5 4 +0.0030 .6664 - 7.5 4 +0.0008 41268.6866 0.0 5 -0.0003 .6869 0.0 5 0.0 .6860 0.0 5 -0.0009 41281.5571 24.0 4 +0.0020 .5566 24.0 4 +0.0015 .5561 24.0 4 +0.0010 41315.6031 87.5 4 +0.0010 .6022 87.5 4 +0.0001 .6012 87.5 4 -0.0009 41317.481 91.0 2 +0.002 41563.853 550.5 2 +0.002 41607.836 632.5 1 +0.019 41620.664 656.5 2 -0.021 41630.603 675.0 3 -0.002 ----------------------------------------------------------------------------- RAYMOND H. BLOOMER University of Florida Gainesville, Florida, U.S.A. [FIGURE 1]