Circular No. 5406 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 KOWAL 2 (1991f1) H. Kosai and T. Hirayama, National Astronomical Observatory, Tokyo, report that Masao Ishikawa has discovered a comet, and they provide the following precise positions: 1991 UT R.A. (1950) Decl. m1 Observer Dec. 12.70336 8 32 29.59 - 0 30 54.6 14.0 Ishikawa 12.80011 8 32 29.28 - 0 32 48.8 " 13.72775 8 32 42.18 - 0 56 07.9 " 13.76373 8 32 42.29 - 0 57 04.4 " 13.79457 8 32 42.64 - 0 57 48.1 " 15.79330 8 32 59.91 - 1 47 08.1 " 16.72291 8 33 06.03 - 2 09 38.7 14.0 Kushida 16.74930 8 33 06.05 - 2 10 13.9 " 16.79861 8 33 06.41 - 2 11 34.1 " M. Ishikawa (Fukaya, Saitama). 0.16-m hyperboloid astrograph. Tech-Pan film without filter. Image diffuse without condensation. Measurer S. Hayakawa. Y. Kushida (Yatsugatake South Base Observatory). 0.20-m f/4 hyper- boloid reflector. Comet images diffuse and difficult to measure, especially in right ascension. B. G. Marsden (Harvard-Smithsonian Center for Astrophysics) and T. Kobayashi (Oizumi, Gunma, Japan) have identified the comet with P/Kowal 2 (1979 II), the prediction for which on MPC 13046 requires correction by Delta(T) = -54 days. Marsden provides the following improved orbital elements, which satisfy 16 observations 1979-1991 with mean residual 1".2: Epoch = 1979 Jan. 7.0 ET T = 1979 Jan. 13.6774 ET Peri. = 189.3294 e = 0.560490 Node = 247.2065 1950.0 q = 1.519722 AU Incl. = 15.8032 a = 3.457766 AU n = 0.1532889 P = 6.430 years Epoch = 1991 Oct. 31.0 ET T = 1991 Nov. 4.3598 ET Peri. = 189.5235 e = 0.564287 Node = 247.0738 1950.0 q = 1.499650 AU Incl. = 15.8359 a = 3.441834 AU n = 0.1543544 P = 6.385 years 1991 December 17 Daniel W. E. Green