Circular No. 3079 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Cable Address: SATELLITES, NEWYORK Telex: 921428 Telephone: (617) 864-5758 COMET KOWAL (1977f) C. T. Kowal, Hale Observatories, provides the following precise positions, obtained at Palomar (cf. IAUC 3076): 1977 UT R. A. (1950) Decl. May 17.20174 13 51 22.85 -12 10 28.8 19.18368 13 50 36.15 -12 07 19.5 The following orbital elements, by the undersigned, are presumably preferable to those on IAUC 3076. Changes to the ephemeris given there are: May 17, dR.A. = +0m.01, dDecl. = -0'.1; June 6, -0m.22, +1'.3; June 26, -0m.93, +5'.2; July 16, -2m.17, +11'.8. T = 1977 Feb. 5.58 ET Peri. = 176.18 e = 0.2399 Node = 28.42 1950.0 a = 6.1195 AU Incl. = 4.34 n = 0.06511 q = 4.6511 AU P = 15.1 years PERIODIC COMET COMAS SOLA The following ephemeris is from Handb. Br. Astron. Assoc. for 1977 with an extension into 1978: For dT = +1d 1977/78 ET R. A. (1950) Decl. Delta r dR.A. dDecl. m2 July 16 0 39.75 -10 54.8 3.449 3.880 -0m50 - 4'2 21.1 26 0 41.83 -11 14.3 -0.53 - 4.4 Aug. 5 0 42.33 -11 43.9 3.095 3.777 -0.57 - 4.6 20.7 15 0 41.11 -12 22.8 -0.60 - 4.8 25 0 38.09 -13 09.0 2.801 3.671 -0.63 - 5.0 20.4 Sept. 4 0 33.33 -13 59.5 -0.66 - 5.1 14 0 27.03 -14 50.1 2.597 3.564 -0.67 - 5.0 20.1 24 0 19.61 -15 35.8 -0.68 - 5.0 Oct. 4 0 11.65 -16 11.5 2.504 3.456 -0.68 - 4.8 19.9 14 0 03.85 -16 33.0 -0.66 - 4.6 24 23 56.91 -16 37.5 2.522 3.345 -0.64 - 4.5 19.8 Nov. 3 23 51.43 -16 24.3 -0.61 - 4.3 13 23 47.81 -15 53.8 2.626 3.234 -0.58 - 4.2 19.7 23 23 46.31 -15 07.6 -0.55 - 4.2 Dec. 3 23 46.95 -14 07.7 2.783 3.121 -0.53 - 4.2 19.7 13 23 49.68 -12 56.0 -0.51 - 4.2 23 23 54.35 -11 34.2 2.956 3.008 -0.50 - 4.3 19.6 Jan. 2 0 00.77 -10 03.8 -0.49 - 4.4 12 0 08.77 - 8 26.1 3.117 2.894 -0.49 - 4.6 19.6 22 0 18.19 - 6 42.2 -0.49 - 4.8 Feb. 1 0 28.85 - 4 52.9 3.249 2.780 -0.50 - 5.0 19.5 11 0 40.65 - 2 59.1 -0.51 - 5.2 21 0 53.49 - 1 01.5 3.338 2.668 -0.53 - 5.4 19.4 m2 = 12.5 + 5 log Delta + 10 log r OCCULTATION BY URANUS ON 1977 AUGUST 26 P. Shelus and F. Benedict, Department of Astronomy, University of Texas at Austin, inform us that there will be a near-central occultation of a faint blue star (magnitude ~ 13.5-14, spectral type A5) by Uranus on Aug. 26. The star's position, derived from a glass copy of the Palomar Sky Survey, is R.A. = 14h23m07s.02, Decl. = -13o47'36".5 (equinox 1950.0). Computations by the undersigned indicate that the minimum geocentric separation of the centers of the star and Uranus will be 0".6 at 2h18m.4 UT and that the semiduration of the occultation will be 21m.3. Local circumstances for the mid-times of the occultations by the eastern and western sides of the epsilon ring are given below. The absolute times are uncertain by several minutes, but relative times should be reasonably correct. UT UT UT UT Fort Davis 1h48m6 2h55m1 La Serena 1h50m6 2h58m3 Williams Bay 1 48.8 2 54.8 Caracas 1 50.9 -- Washington 1 49.4 -- La Plata 1 50.5 -- OCCULTATION OF SAO 99401 BY (2) PALLAS ON 1977 JULY 8 Computations by G. E. Taylor, H.M. Nautical Almanac Office; and by D. W. Dunham, Computer Sciences Corporation, show that the occultation of SAO 99401 (magnitude 8.3, spectral type K0) will be observable under favorable conditions in a 600-km-wide track that crosses the eastern coast of Brazil soon after July 8d21h40m UT. The nominal path is near Salvador, but changes of 0".5 in the relative positions of star and planet could shift it to Rio de Janeiro or to Natal. A central occultation will last for 16 seconds. MXB1730-335 W. H. G. Lewin and J. A. Hoffman, Massachusetts Institute of Technology, report that they followed MXB1730-335 for one hour near May 24d11h UT with the SAS-3 Observatory. No bursts were observed, so it seems that the rapid burster has turned off (cf. IAUC 3075). 1977 May 31 (3079) Brian G. Marsden
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