233 TK4 (LYRAE) (UGSU) Range: 14.9-20.1V Position: 19 13 58.47 +40 44 09.1 (Kryachko, IBVS 5058) Magnitude: V=20.1 (from .dat file) ID RA (2000) DEC X Y N V ERR B-V ERR a) Comparison star sequence 1 19 14 14.8 +40 49 03 179 294 1 11.438 0.000 0.564 0.000 2 19 13 52.3 +40 45 28 -76 79 1 11.822 0.000 0.796 0.001 3 19 13 50.5 +40 41 26 -97 -163 1 12.065 0.001 0.962 0.001 4 19 14 01.5 +40 39 07 28 -302 1 12.539 0.001 0.799 0.001 5 19 13 45.5 +40 44 22 -153 13 1 12.860 0.001 1.003 0.001 6 19 14 02.6 +40 49 36 40 327 1 13.380 0.001 1.195 0.002 7 19 13 34.9 +40 43 24 -274 -45 1 13.702 0.001 0.671 0.002 8 19 13 51.2 +40 44 43 -88 34 1 14.199 0.002 0.605 0.003 9 19 13 57.4 +40 44 41 -18 32 1 14.599 0.002 0.683 0.004 10 19 14 01.5 +40 43 05 29 -64 1 15.115 0.003 0.418 0.004 11 19 13 46.2 +40 45 43 -146 94 1 15.310 0.003 0.894 0.007 12 19 13 36.2 +40 43 48 -260 -21 1 15.579 0.004 0.882 0.008 13 19 13 54.5 +40 42 21 -51 -108 1 15.848 0.005 0.975 0.011 14 19 13 59.7 +40 43 11 8 -58 1 16.322 0.007 0.735 0.013 15 19 13 55.2 +40 43 34 -43 -35 1 17.105 0.013 1.118 0.042 b) Wide-colour extension for CCD calibration 19 14 36.3 +40 50 54 423 404 1 13.525 0.001 0.457 0.001 19 13 39.3 +40 38 16 -224 -353 1 13.494 0.001 1.217 0.002 Notes: 1. This single night sequence is expected to have errors of about +/-0.02 magnitude. 2. TK4 has a very close very red companion only 3 arcsec north of the variable. The companion is of similar magnitude to TK4 at quiescence, namely about magnitude 20. 3. There is a bright star on the west edge of this field at 19h 13m 22.4s +40d 43' 53" with a reliable Tycho-2 magnitude of 9.29+/-0.02. 4. For discovery information see Kryachko, T.V., IBVS 5058, 2001. Bruce Sumner 19 October 2001