COMMISSIONS 27 AND 42 OF THE IAU INFORMATION BULLETIN ON VARIABLE STARS Number 4037 Konkoly Observatory Budapest 31 May 1994 HU ISSN 0374 - 0676 IMPROVED ASTROMETRY FOR VARIABLE STARS In the course of preparing finder charts for variable stars, I have used the HST Guide Star Catalogue extensively as a source of reliable positions. Many of the variables I have charted since 1990 are found in the GSC, and a list of forty stars is presented, as Table 1. The positions are all taken from the GSC. In the case of multiple GSC positions, the mean value is given. All stars have been identified by reference to photographs or older charts. Several very interesting variables are not in the GSC, and improved positions have been measured from photographs, relative to GSC stars. Data for five stars are in Table 2. Clarifying remarks are given below for four stars. TZ Cen. The star GSC 8989-00095 agrees well with TZ Cen as regards position and magnitude. There appears to be no identification problem, contrary to the remark given in the GCVS. NSV 14319. Near S5150 = RZ Gruis. The position given in the NSV is spurious, as none was given in the paper by Siedel (1957), and the finder chart in that paper appears to have been misinterpreted (Wenzel,1990). The star is also wrongly plotted on VSS, RASNZ chart 954 (Bateson and Morel,1990). The variable is really 2' south of the marked position. Following the advice given by Wenzel, I find that NSV 14319 = GSC 8010-00313 (m=12.23). Position in Table 1. [Note that Siedel's finder chart has North at top, in error. 'N' should be at bottom.) NSV 4223 Pyx. Se star. Observed by P. Camilleri on patrol films. In Catalogue of Galactic S Stars (Stephenson 1984), which places it 1.5 arc min south-following CoD-32d5649 (9.7). Both stars are clearly seen on Union Obs. chart, with NSV 4223 near maximum (10 mag). NSV 4223 is not in DM catalogues, nor in GSC. Contrary to NSV, and the Catalogue of S Stars, NSV 4223 is not equal with CoD-32d5649. New Variable in Vulpecula. See IBVS 3604. This variable is superimposed on the planetary nebula M27, a popular subject for astrophotography. Many photos in popular books and magazines were searched for images of the variable. One such photo is in Sky & Tel., Aug. 1993, p. 66, where the variable is at about 14.3V. A mean position was determined relative to GSC stars (two determinations using different sets of stars). The improved position appears in Table 2. Table 1: Positions of Variable Stars from Guide Star Catalogue. Name GSC No. R.A. (J2000) Dec. Remarks h m s d ' " WW Cet 5263-00415 0 11 24.81 - 11 28 42.9 R For 6433-00295 2 29 15.28 - 26 5 54.5 R Ret 8872-00420 4 33 32.82 - 63 1 46.2 TV Col 7059-00509 5 29 25.47 - 32 49 4.2 ST Pup 7100-00288 6 48 56.36 - 37 16 33.9 Z CMa 5389-01211 7 3 43.07 - 11 33 5.7 QS Mon 5396-00840 7 25 13.06 - 7 52 42.7 V694 Mon 5396-01135 7 25 51.24 - 7 44 7.6 DQ Pup 6542-00396 7 29 11.16 - 26 10 32.1 PP Pup 8133-02109 7 35 52.28 - 46 32 17.0 YZ CMi 0183-02190 7 44 40.50 + 3 33 15.3 SS Pup 6548-02718 7 46 38.29 - 26 20 35.4 ET Pup 6561-01413 7 54 37.20 - 28 4 58.6 R Cha 9394-01962 8 21 46.91 - 76 21 18.5 W Cha 9394-02775 8 28 22.17 - 76 33 43.1 V336 Car 8576-00085 8 32 25.23 - 57 2 14.2 TX Pyx 7141-00233 8 42 30.62 - 32 20 32.2 AM Car 8943-03285 10 14 29.40 - 60 43 27.9 FU Car 8626-02521 10 41 0.34 - 59 23 12.9 V426 Car 8626-00464 10 47 56.89 - 59 8 54.7 V432 Car 8959-00431 11 84 0.30 - 60 42 51.7 FQ Car 8959-00065 11 10 13.00 - 60 50 50.7 U Cen 8650-01846 12 33 30.63 - 54 39 34.5 EX Hya 6709-00694 12 52 24.42 - 29 14 56.7 V496 Cen 8989-01422 13 3 10.76 - 60 52 38.9 TZ Cen 8989-00095 13 4 7.24 - 60 45 57.5 V398 Cen 8990-03516 13 19 55.17 - 60 42 26.8 NSV 6200 8990-03462 13 21 37.61 - 61 34 14.9 NSV 6202 8990-02176 13 21 42.89 - 60 49 46.4 RZ Vir 0300-00285 13 21 50.40 + 1 50 49.9 U Mus 8998-02133 13 25 3.34 - 64 39 47.8 XY Mus 8999-02850 13 27 33.09 - 65 4 3.0 NSV 6282 8666-00587 13 31 5.25 - 55 0 0.6 BV Cen 8666-00998 13 31 19.52 - 54 58 33.7 BC Cen 8677-01439 14 2 29.30 - 58 33 25.0 NSV 6525 9013-00792 14 3 22.95 - 63 57 28.7 NSV 6536 9013-00637 14 5 33.59 - 64 20 1.0 NSV 6545 9009-01513 14 6 0.09 - 62 4 22.6 Z Aps 9252-01914 14 6 54.98 - 71 22 16.2 V854 Cen 7810-00220 14 34 49.35 - 39 33 19.8 NSV 7190 9034-00653 15 42 25.79 - 65 39 8.5 HK TrA 9034-03378 15 42 30.92 - 65 38 47.6 GL TrA 9031-03143 15 43 27.51 - 65 27 29.7 AF Nor 8705-03082 15 52 38.05 - 56 38 31.4 SS Nor 8723-00573 16 13 21.89 - 59 46 56.6 Near QR Nor. TX Oph 0406-00580 17 4 0.10 + 4 59 1.1 AE Ara 8347-01978 17 41 4.93 - 47 3 27.0 V2203 Oph 0424-00304 17 49 43.32 + 4 28 24.4 AR Pav 9080-00788 18 20 27.92 - 66 4 41.8 GU Sgr 6844-03878 18 24 15.58 - 24 15 26.1 V4018 Sgr 6869-00806 18 25 26.95 - 28 35 57.5 NSV 11753 3132-00900 19 6 54.38 + 44 2 55.5 KQ Aql 0463-01244 19 12 22.87 + 1 33 8.6 HR Del 1642-00998 20 42 20.38 + 19 9 39.9 LQ Del 1642-00526 20 42 49.47 + 19 11 7.7 EV Aqr 0526-01562 21 6 17.85 + 0 52 43.5 U PsA 6960-00988 22 2 29.49 - 27 53 7.0 S PsA 6960-01450 22 3 45.82 - 28 3 4.0 RU Peg 1145-00536 22 14 2.58 + 12 42 11.4 NSV 14319 8010-00313 22 48 16.47 - 42 54 22.7 Table 2: positions of Variable Stars not in Guide Star Catalogue. Name GSC No. R.A. (J2000) Dec. Remarks h m s d ' " NSV 4223 .......... 8 43 41.0 - 32 31 40 CGSS 543. TT Cen .......... 13 19 35.5 - 60 46 45 UU Cen .......... 13 22 6.4 - 61 18 37.4 QR Nor .......... 16 13 20.0 - 59 47 30 Near SS Nor. ... Vul .......... 19 59 29.8 + 22 45 13 Near M27. I wish to thank the following people for providing useful material: Paul Camilleri for his observations of NSV 4223; Robert H. McNaught, Siding Spring Observatory, for identifying SS and QR Nor on UK Schmidt plates; Albert F. Jones of Nelson, New Zealand, for providing a copy of Wenzel's letter. M. Morel 18 Elizabeth Cook Drive, Rankin Park NSW 2287 Australia References: Bateson, F.M. & Morel, M. 1990. Charts for Southern Variables, Series 21. Publ. by Astronomical Research Ltd, Tauranga, NZ. Siedel, Th. 1957. MVS 336. Stephenson, C.B. 1984. Publs. Warner And Swasey Obs., 3, No. 1. [BIBCODE 1984PW&SO...3....1S ] Wenzel, W. 1990. Private communication to A.F. Jones.