Central Bureau for Astronomical Telegrams

IAUC 6017: 1993e; 1993v

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                                                  Circular No. 6017
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


PERIODIC COMET SHOEMAKER-LEVY 9 (1993e)
     R. M. West, European Southern Observatory, has measured the
nuclei on CCD images obtained during July 1-8 by O. Hainaut,
R. Schulz, M. Carollo, C. Alard and A. Cimatti with the 3.5-m New
Technology Telescope and 1.5-m Danish telescope.  Reductions
were with the help of southern Sky Atlas plates and provisional
Hipparcos reference-star positions provided by M. Perryman and C.
Turon.  S. Nakano, Sumoto, Japan, has computed improved orbits
and the following times (corrected for light time) for the impacts
on Jupiter: A = 21, July 16.826 UT; B = 20, 17.113; C = 19, 17.287;
D = 18, 17.483; E = 17, 17.625; F = 16, 18.014; G = 15, 18.308;
H = 14, 18.805; K = 12, 19.425; L = 11, 19.919; N = 9, 20.428;
P = 8 (= P2 = 8b), 20.624; Q = 7 (= Q1 = 7a), 20.831; R = 6, 21.223;
S = 5, 21.627; T = 4, 21.758; U = 3, 21.907; V = 2, 22.166; W = 1, 22.330.
Comparison with computations by P. W. Chodas and D. K. Yeomans,
Jet Propulsion Laboratory, suggests that the uncertainty is now around
+/- 0.005 day for almost all these nuclei, the remaining uncertainty
being mainly because most of the earlier observations were reduced using
the STScI Guide Star Catalogue.  Using the tidal-disruption model
of Z. Sekanina, Chodas and Yeomans provide less certain impact times
for lost and less well observed fragments: J = 13, July 19.11 UT;
M = 10, 20.24; P1 = 8a, 20.69; Q2 = 7b, 20.81.  They add that a
significant number of particles beyond the eastern end of
the nuclear train should now already have begun to strike Jupiter.


COMET McNAUGHT-RUSSELL (1993v)
     Ephemeris continuation from the orbital elements on MPC 23651:

1994 TT     R. A. (2000) Decl.     Delta      r    Elong. Phase      m1
July  7    15 11.37    +54 28.7    1.579    1.852   88.3   33.3     13.2
     17    15 27.83    +49 55.6    1.718    1.981   89.0   30.9     13.6
     27    15 43.04    +45 32.2    1.863    2.110   89.2   28.8     14.1
Aug.  6    15 57.57    +41 21.3    2.017    2.237   88.7   27.0     14.5
     16    16 11.75    +37 25.5    2.179    2.363   87.5   25.4     14.9
     26    16 25.73    +33 47.1    2.350    2.487   85.7   23.9     15.3
Sept. 5    16 39.61    +30 27.2    2.529    2.610   83.2   22.6     15.7

     Total visual magnitude estimates: Apr. 1.15 UT, 6.2
(C. E. Spratt, Victoria, BC, 11 x 80 binoculars); 15.93, 7.6 (B. H.
Granslo, Fjellhamar, Norway, 0.20-m reflector); May 2.07, 7.4 (J. E.
Bortle, Stormville, NY, 10 x 50 binoculars); 15.88, 9.5 (L. Szentasko,
Veresegyhaz, Hungary, 0.33-m reflector); June 9.34, 11.1 (A. Hale,
near Orogrande, NM, 0.41-m reflector).


1994 July 9                    (6017)              Brian G. Marsden

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