7. GX CASSIOPEIAE (UGSU) Range: 13.3-18.7V Position: 00 49 01.46 +56 52 43.9 (J2000, from .dat file) Magnitude: V=18.747 B-V=0.169 (Henden, single night) ID RA (2000) DEC X Y N V ERR B-V ERR a) Comparison star sequence 1 00 48 56.2 +56 48 57 -43 -227 3 11.724 0.097 1.462 0.125 2 00 48 26.6 +56 55 10 -286 146 2 12.451 0.020 1.451 0.030 3 00 48 44.7 +56 51 00 -138 -104 4 12.988 0.021 0.766 0.023 4 00 48 28.6 +56 51 48 -269 -56 4 13.280 0.006 0.439 0.016 5 00 49 19.3 +56 52 40 146 -4 4 13.833 0.016 0.843 0.006 6 00 49 24.2 +56 52 22 186 -22 4 14.026 0.005 0.762 0.007 7 00 49 22.4 +56 52 06 171 -38 4 14.610 0.045 1.359 0.054 8 00 48 49.4 +56 52 26 -99 -18 4 14.729 0.000 0.722 0.009 9 00 49 15.3 +56 51 03 113 -101 4 14.933 0.000 1.025 0.009 10 00 48 53.3 +56 54 41 -68 117 2 15.103 0.044 0.799 0.015 11 00 48 52.3 +56 53 54 -75 70 4 15.356 0.008 0.930 0.011 12 00 48 59.6 +56 52 13 -16 -31 4 15.729 0.009 1.305 0.012 13 00 49 01.8 +56 51 03 2 -101 4 16.156 0.006 0.861 0.005 14 00 48 56.5 +56 53 19 -41 35 4 16.465 0.011 0.980 0.015 15 00 49 01.3 +56 53 06 -1 22 4 16.969 0.028 0.660 0.014 16 00 48 54.8 +56 51 51 -55 -53 4 17.603 0.028 0.951 0.013 17 00 49 03.5 +56 53 16 17 32 4 18.114 0.034 1.147 0.040 18 00 48 58.0 +56 52 57 -29 13 4 18.166 0.048 0.879 0.082 19 00 49 00.5 +56 52 31 -9 -13 4 18.972 0.095 0.849 0.188 20 00 49 02.7 +56 52 40 10 -4 3 19.542 0.070 0.805 0.128 b) Wide-colour extension for CCD calibration 00 48 16.6 +56 49 42 -368 -182 3 12.785 0.018 0.418 0.010 00 48 39.8 +56 57 05 -177 261 4 13.198 0.015 0.472 0.021 00 49 34.8 +56 51 39 273 -65 4 15.036 0.005 1.402 0.008 00 48 18.7 +56 47 03 -351 -341 4 15.494 0.014 1.473 0.008 Notes: 1. Star #1 is saturated, its magnitude and colour are approximate. 2. This is a very crowded field, and the faint stars 15, 16, 17, 18, 19 and 20 have large errors because of this. They should be used with due care. 3. There is an revised preliminary AAVSO chart dated 05/1993, which has several stars in common with this sequence: ID Henden AAVSO V V 1 11.724 11.3 2 12.451 11.0 see note below 3 12.988 13.4 5 13.833 14.1 7 14.610 14.5 8 14.729 15.2 12 15.729 16.0 13 16.156 16.4 4. The AAVSO star 11.0 is misplotted on the 1993 chart. In reality 11.0 is the brighter star about 100" west of the indicated position. It was not measured as part of this sequence. 5. Superhumps detected by Nogami in 1998 verifying this as an SU UMa-type dwarf nova. Varies at minimum between V=18.3 and V=18.7. Bruce Sumner Revised 31 July 1999