178 RZ SAGITTAE (UGSU) Range: 12.0-17.5V Position: 20 03 18.49 +17 02 52.1 (J2000, Henden astrometry) Magnitude: 17.509 B-V=0.437 (in .dat file) ID RA (2000) DEC X Y N V ERR B-V ERR a) Comparison star sequence 1 20 03 28.3 +17 05 25 141 153 3 11.020 0.010 1.728 0.011 2 20 03 34.7 +17 03 42 232 50 3 11.223 0.014 0.708 0.015 3 20 03 18.2 +17 04 56 -5 124 3 11.478 0.013 1.150 0.016 4 20 03 32.6 +17 03 33 202 41 3 11.828 0.014 0.435 0.020 5 20 02 58.4 +17 00 38 -288 -134 3 12.055 0.023 0.456 0.019 6 20 03 16.4 +17 04 19 -31 87 3 12.526 0.012 1.335 0.015 7 20 03 22.0 +17 03 43 50 51 3 12.794 0.011 1.351 0.010 8 20 03 00.3 +17 01 34 -261 -78 3 13.133 0.021 0.938 0.013 9 20 03 39.6 +17 01 53 303 -59 3 13.210 0.014 1.100 0.015 10 20 03 02.9 +17 02 01 -224 -51 3 13.681 0.023 1.251 0.018 11 20 03 34.6 +17 02 07 230 -45 3 13.846 0.013 1.594 0.014 12 20 03 26.0 +17 03 39 108 47 3 13.953 0.011 1.253 0.014 13 20 03 16.3 +17 01 22 -32 -90 3 14.076 0.014 1.323 0.010 14 20 03 19.6 +17 01 39 16 -73 3 14.339 0.023 0.782 0.009 15 20 03 12.0 +17 00 55 -94 -117 3 14.643 0.019 0.778 0.013 16 20 03 16.0 +17 02 04 -35 -48 3 14.971 0.016 1.305 0.047 17 20 03 20.9 +17 03 36 34 44 3 15.490 0.009 0.929 0.016 18 20 03 17.8 +17 02 25 -9 -27 3 15.897 0.044 0.745 0.086 19 20 03 17.7 +17 01 41 -11 -71 3 16.600 0.080 0.971 0.124 20 20 03 17.3 +17 03 24 -18 32 3 16.892 0.057 0.958 0.054 21 20 03 17.9 +17 02 47 -9 -5 2 17.861 0.019 0.818 0.253 b) Wide-colour extension for CCD calibration 20 03 38.6 +17 06 24 288 212 3 13.022 0.014 1.847 0.010 20 03 08.9 +17 00 20 -138 -152 3 12.959 0.011 1.849 0.012 20 03 37.5 +17 01 29 272 -83 3 12.011 0.014 1.964 0.010 Notes: 1. This sequence is unapologetically based on the 1970 AAVSO preliminary chart 195816f, where there is given a sequence that has beenused by visual observers for many decades. However the AAVSO sequence is considerably in error, with the bright end of the sequence being too bright, while at the faint end the AAVSO magnitudes are over one magnitude too faint. The AAVSO chart needs to be corrected as soon as possible. In addition the RASNZ chart 333 for this variable also repeats the erroneous AAVSO sequence. Henden AAVSO Misselt star V B-V v V B-V 2 11.223 0.708 109 4 11.828 0.435 116 5 12.055 0.456 120 6 12.526 1.335 125 12.538 1.343 7 12.794 1.351 129 12.829 1.368 8 13.133 0.938 134 9 13.210 1.100 134 10 13.681 1.251 143 11 13.846 1.594 144 12 13.953 1.253 147 13.997 1.297 13 14.076 1.323 150 14.125 1.332 14 14.339 0.782 153 16 14.971 1.305 150 14.984 1.341 18 15.897 0.745 d 2. The chart by Bouma dated 18 June 2000 includes a sequence based on Misselt and Henden/Honeycutt photometry. It differs considerably from the sequence given here, but for visual observers it is equally as good as the sequence presented here, as both sequences are based on accurate CCD(V) photometry. 3. The red star in the above Table b) with V=12.011 and B-V=1.964 is shown on the AAVSO chart as 119. This star is too red to be included in this new comparison star sequence. 4. TY Sge is confirmed as a constant star, with V=13.712 and B-V=0.634. Bruce Sumner 24 July 2000