Circular No. 5360 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Telephone 617-495-7244/7440/7444 (for emergency use only) TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505 MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN PERIODIC COMET McNAUGHT-HUGHES (1991y) R. H. McNaught provides the following additional measurements from films taken with the Uppsala Southern Schmidt telescope at Siding Spring: 1991 UT R.A. (1950) Decl. Oct. 2.55556 23 09 09.64 -18 47 58.9 2.73611 23 09 05.38 -18 47 46.3 5.52552 23 08 06.55 -18 44 11.9 The following preliminary orbital elements, from the six available observations, indicate that this is a short-period comet: T = 1991 June 29.248 ET Peri. = 231.290 e = 0.39604 Node = 87.864 1950.0 q = 2.17255 AU Incl. = 7.304 a = 3.59718 AU n = 0.144464 P = 6.82 years 1991 ET R.A. (1950) Decl. Delta r m1 Oct. 1 23 09.79 -18 49.1 1.345 2.277 16.5 6 23 07.96 -18 43.4 11 23 06.70 -18 31.9 1.427 2.299 16.7 16 23 06.05 -18 15.0 21 23 06.04 -17 53.0 1.527 2.323 16.9 26 23 06.66 -17 26.5 31 23 07.90 -16 55.9 1.642 2.349 17.1 V1017 SAGITTARII K. Sekiguchi, South African Astronomical Observatory; and D. W. Latham, Center for Astrophysics, report: "Spectra of V1017 Sgr ob- tained Aug. 6-13 at SAAO, Sutherland, are similar to 1990 spectra when the star was at minimum. By Sept. 10-17, the spectra showed a strengthened blue continuum. Spectra obtained Oct. 2-4 show a blue continuum and narrow (FWZI about 700 km/s) Balmer emission lines, He I and II, and a weak 464.0-nm blend, with He II 468.6-nm the strong- est line. The observed features are similar to those seen in 1973 (Vidal and Rodgers 1974, PASP 86, 26) and are consistent with a brightened accretion disk (cf. Webbink et al. 1987, Ap.J. 314, 653)." 1991 October 7 Daniel W. E. Green