53. FO AQUILAE (UGSS) Range: 13.6-17.3V Position: 19 16 38.17 +00 07 37.4 (J2000, from .dat file) Magnitude: V=17.282 B-V=0.715 (in .dat file) ID RA (2000) DEC X Y N V ERR B-V ERR a) Comparison star sequence 1 19 16 38.6 +00 11 23 6 226 3 11.778 0.026 1.470 0.007 2 19 16 50.9 +00 05 47 191 -110 3 12.277 0.015 1.566 0.016 3 19 16 36.2 +00 08 02 -31 25 3 12.515 0.026 1.800 0.019 4 19 16 28.8 +00 06 14 -141 -83 3 12.710 0.024 1.521 0.022 5 19 16 34.6 +00 08 43 -54 66 3 13.289 0.013 0.989 0.019 6 19 16 26.1 +00 09 16 -181 98 3 13.665 0.009 2.059 0.016 7 19 16 47.7 +00 06 27 142 -70 3 13.922 0.018 1.045 0.019 8 19 16 33.9 +00 07 23 -64 -15 3 14.603 0.039 1.633 0.041 9 19 16 47.8 +00 08 28 143 51 3 14.679 0.014 1.430 0.017 10 19 16 38.4 +00 08 30 3 53 3 15.150 0.009 1.550 0.012 11 19 16 40.0 +00 07 33 26 -4 3 15.491 0.021 1.129 0.026 12 19 16 33.3 +00 08 31 -73 53 3 15.614 0.013 0.975 0.034 13 19 16 32.0 +00 08 01 -93 23 3 16.025 0.028 1.055 0.016 14 19 16 37.2 +00 07 20 -15 -17 3 16.290 0.014 0.700 0.038 15 19 16 39.4 +00 07 22 17 -15 3 16.483 0.056 1.076 0.011 16 19 16 38.6 +00 07 06 6 -31 3 17.084 0.026 1.544 0.042 17 19 16 36.4 +00 07 30 -27 -7 3 17.269 0.018 0.973 0.007 18 19 16 38.0 +00 07 35 -2 -2 1 18.692 0.025 1.299 0.040 b) Wide-colour extension for CCD calibration 19 16 21.2 +00 05 43 -255 -115 3 12.409 0.027 0.554 0.020 19 16 44.0 +00 11 54 87 257 4 13.376 0.014 0.628 0.016 19 16 18.4 +00 09 21 -297 104 3 12.723 0.054 2.189 0.009 19 16 17.8 +00 11 45 -307 248 3 15.383 0.013 2.154 0.027 Notes: Star 18 is a very close companion to FO Aql and is located only 2.9" SW. This is an extremely reddened field, with FO Aql being in the top bluest 1% of all stars in this region. There is a possibility that the star identified at V=17.282 as FO Aql is in fact an extremely close unresolved double star. This is determined by astrometry obtained by Arne Henden when FO Aql is faint compared to astrometry of the outbursting object. Available astrometry gives: Red star 19 16 38.156+/-0.035 +00 07 36.883+/-0.216 V=17.282 FO Aql 19 16 38.170+/-0.032 +00 07 37.369+/-0.055 V=13.794 Diference (red star-FO Aql): RA -0.198 arcsec Dec. -0.486 arcsec Therefore it is possible that FO Aql is slightly northeast of the companion, but close enough that it is unresolvable. There is an AAVSO sequence on a chart dated July 1977. There is one additional faint star measured by N. Vogt in Publ. No. 8 (VSS RASNZ, 1980). ID Henden AAVSO RASNZ V V V 2 12.277 12.0 3 12.515 11.8 4 12.710 12.5 5 13.289 13.0 6 13.665 13.6 8 14.603 14.5 14 16.290 16.2 Bruce Sumner Revised 23 July 1999