156 V446 HERCULIS (NA) Range: 2.8-18.8p Position: 18 57 21.61 +13 14 29.7 (J2000, Henden, psf-fitting) Magnitude: V=16.121 B-V=0.472 (from .dat file) ID RA (2000) DEC X Y N V ERR B-V ERR a) Comparison star sequence 1 18 57 31.2 +13 16 46 139 137 7 12.518 0.054 1.282 0.075 2 18 57 23.6 +13 13 16 30 -73 7 12.586 0.045 0.614 0.053 3 18 57 09.4 +13 16 11 -178 102 7 13.236 0.016 0.891 0.013 4 18 57 02.7 +13 12 11 -276 -138 7 13.419 0.014 1.213 0.015 5 18 57 40.2 +13 17 11 271 162 7 13.777 0.019 0.526 0.012 6 18 57 22.8 +13 14 17 18 -13 7 14.048 0.019 0.941 0.018 7 18 57 15.7 +13 15 11 -86 42 7 14.459 0.011 0.872 0.017 8 18 57 26.4 +13 14 53 70 24 7 15.173 0.022 0.878 0.011 9 18 57 20.9 +13 14 13 -10 -16 7 15.693 0.015 2.132 0.058 10 18 57 20.4 +13 13 55 -18 -34 7 16.103 0.019 1.674 0.029 11 18 57 17.3 +13 13 46 -63 -43 7 16.506 0.032 1.868 0.080 12 18 57 27.1 +13 14 17 81 -12 7 17.414 0.043 1.270 0.036 13 18 57 20.2 +13 14 20 -20 -9 7 18.028 0.073 1.459 0.379 b) Wide-colour extension for CCD calibration 18 57 37.9 +13 09 38 238 -291 5 12.947 0.016 0.492 0.014 18 57 25.1 +13 08 56 51 -333 4 14.329 0.017 0.499 0.010 18 57 44.6 +13 10 55 336 -214 2 12.511 0.058 0.519 0.058 18 57 15.2 +13 16 13 -93 104 7 14.263 0.013 2.272 0.021 18 57 38.7 +13 17 13 249 164 7 14.511 0.027 2.295 0.023 18 57 31.8 +13 13 02 150 -87 7 13.319 0.011 2.333 0.015 Notes: 1. Stars 1 and 2 are saturated, and their magnitudes should be used for guidance only. 2. There is a photoelectric sequence of some of the brighter stars in this field in a paper by Stienon, PASP,75,45S,1963. The stars common to the two sequences are: Henden Stienon Star V B-V V B-V 1 12.518 1.282 12.49 1.46 2 12.586 0.614 12.65 0.61 3 13.236 0.891 13.31 0.91 4 13.419 1.213 13.46 1.39 3. The bright star HD 175959 is located only 1.7 arcmin north of the variable. It was measured by Stienon with V=8.90 B-V=1.55. 4. This field is predominantly populated with red stars, and it is impossible to create a sequence composed of stars of similar colour. Observers should be aware that the bright half of this sequence are mostly blue stars, whereas the fainter half of the sequence are mostly red stars. 5. There is a triplet of companion stars to V446 Her. The stars are labelled B,C,D, where B and C are identified on the finding chart in Honeycutt, et al. 1998, ApJ 495, 933, and star D is the faint companion due west of the variable. As above, the RA and DEC offsets are in arcsec, positive east and north. Star RA DEC V err B-V err V-R err R-I err B 1.49 -2.75 17.90 0.02 1.33 0.04 0.78 0.03 0.67 0.02 C -2.18 -2.53 18.51 0.02 1.28 0.08 0.74 0.01 0.75 0.01 D -2.62 -0.39 20.87 0.25 1.10 0.52 1.08 0.24 0.75 0.25 These numbers are more reliable than the values in the Honeycutt paper since the current images had better seeing and higher signal/noise. 6. V446 Her itself is at 18:57:21.61 +13:14:29.7 (J2000). This is improved over the Honeycutt paper through the use of USNO-A2.0. Since the variable is about V=16.5 and B-V=0.27, you must be careful to remove these three stars when doing photometry or you will report the variable as being too bright; this is especially true at the red wavelengths or with unfiltered photometry. Arne Henden and Bruce Sumner 10 September 2000