Photoelectric Minima of Eclipsing Binaries, 1990 - 1991 Tristram Brelstaff [Originally published in British Astronomical Association Variable Star Section Circular No 91, 16-17, 1997] This report covers photoelectric timings of minimum of eclipsing binaries made in the years 1990 and 1991. The names of the observers and the numbers of observations and timings contributed by each are listed in Table 1. The times of minimum derived from the observations are listed in Table 2. A colon (':') following a timing indicates that it is uncertain, either because the observations show unusually large scatter or else because the rising or fading limb was poorly covered. The epoch and O-C values are relative to the linear elements given in the 4th Edition of the GCVS. For various reasons, this report has been published after those for 1992-1995. To help clear up any confusion that might arise from this, Table 3 explicitly lists where the photoelectric results for these years can be found. Before 1990, the photoelectric results were included with the visual ones in the main Eclipsing Binary Program reports. The visual results for 1990 onwards will be published in the future. Table 1. Observer Totals ------------------------------------------------------------------------- Observer No. Obs. No. Timings ------------------------------------------------------------------------- A J Hollis (HO) 131 3 J E Isles (IS) 407 15 R D Pickard (PI) 87 3 J Watson (TW) 188 11 ------------------------------------------------------------------------- Total 813 32 ------------------------------------------------------------------------- Table 2. Observed Minima ------------------------------------------------------------------------- Star Epoch JD Hel O-C No Observer Filter Notes (244...) (d) ------------------------------------------------------------------------- OO Aql 19456 8473.2919: -0.0070: 8 IS B OO Aql 19456 8473.2931: -0.0058: 8 IS V Sigma Aql 13341 8505.3274 0.1117 9 IS V VW Cep 15626.5 8506.4332 -0.0630 16 PI V VW Cep 15627 8506.5776 -0.0578 19 PI V VW Cep 15842 8566.4124 -0.0606 11 TW V VW Cep 15857 8570.5836 -0.0641 14 TW V VW Cep 15953 8597.3031 -0.0628 10 TW V VW Cep 15978 8604.2602 -0.0636 14 TW V VW Cep 16032 8619.2908 -0.0620 12 PI V GK Cep 9981 8038.5514 0.0621 24 TW V 1 GK Cep 10051.5 8104.5485 0.0601 22 TW V 2 AI Dra 4008 8096.4832 0.0073 19 TW V SW Lac 8784 8092.5473 -0.0128 17 TW V CM Lac 13131 8097.5184 -0.0030 15 TW V UV Leo 16540.5 8366.4373 0.0087 43 HO V WZ Oph 3060.5 8452.3967 0.0016 71 IS V V451 Oph 1658 8476.3237 0.0023 19 IS V V451 Oph 1658 8476.3243 0.0029 19 IS B V502 Oph 16046 8449.3324 -0.0477 36 IS V V502 Oph 16121 8483.3310 -0.0536 19 IS V V502 Oph 16121 8483.3349 -0.0497 19 IS B V566 Oph 16203 8473.3720 0.0212 15 IS V V566 Oph 16203 8473.3743 0.0235 15 IS B V839 Oph 19577 8455.3877 0.0734 31 IS B V839 Oph 19577 8455.3895 0.0752 31 IS V V839 Oph 19638 8480.3365 0.0735 22 IS V V839 Oph 19638 8480.3370 0.0740 22 IS B W UMa 6740 8014.4417 -0.0135 12 TW V W UMa 6743 8015.4435 -0.0126 11 TW V AG Vir 4595 8385.4400 0.0452 17 HO V AH Vir 6311.5 8386.5062 0.0524 71 HO V ----------------------------------------------------------------------- Notes: 1. Includes 9 observations from JD 2448084. 2. Includes 11 observations from JD 2448091. Table 3. Publication of the 1990-1995 Photoelectric Timings ------------------------------------------------------------------------- Year Where Published ------------------------------------------------------------------------- 1990-91 This report 1992-93 VSSC 81, 4-5, 1994 1994 VSSC 84, 2, 1995 1995 VSSC 90, 16, 1996 -------------------------------------------------------------------------