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IAUC 2850: 1975j; 1975k

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                                                  Circular No. 2850
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
Western Union: RAPID SATELLITE CAMBMASS


COMET MORI-SATO-FUJIKAWA (1975j)
     The following positions have been reported:

     1975 UT             R. A. (1950) Decl.        m1    Observer
     Oct.  6.79236     8 21 50.5    + 2 35 52     10     Suzuki
           7.41979     8 22 20.01   + 2 12 50.2          Moore
           7.44410     8 22 21.14   + 2 11 55.3            "
           8.77368     8 23 22.60   + 1 22 03.2   10     Shibasaki
           8.78112     8 23 23.00   + 1 21 45.6            "
           9.79097     8 24 09.10   + 0 43 03.1   10     Kojima
           9.81389     8 24 09.79   + 0 42 10.2            "
          11.72014     8 25 34.8    - 0 32 57     10     Herald

K. Suzuki (JCPM Oi Station).  Measurer: T. Urata.  Communicated by
   K. Osawa.
E. Moore (Joint Observatory for Cometary Research).  37-cm f/2
   Schmidt camera.  Measurer: E. Tedesco.  Communicated by Tedesco.
H. Shibasaki (Tokyo Astronomical Observatory).  Measurer: H. Kosai.
   Communicated by Osawa.
N. Kojima (Ishiki, Aichi).  Measurer: Kosai.  Communicated by Osawa.
D. Herald (Woden, near Canberra).  A scaled position.

     The comet is diffuse with a central condensation, but without
a tail.  The following parabolic orbits, by Z. Sekanina, satisfy,
respectively, the Oct. 6-11 and 7-9 observations within 3".  The
second set of elements leaves residuals of -4" on Oct. 6 and -5" on
Oct. 11 in declination, while the fits in right ascension are
almost perfect.  The ephemeris is from the first orbit.

       T = 1975 Dec. 23.50 ET        T = 1975 Dec. 20.21 ET
   Peri. = 243.98                Peri. = 240.99
   Node  = 277.82   1950.0       Node  = 277.62   1950.0
   Incl. =  90.77                Incl. =  89.68
       q =   1.6371 AU               q =   1.6800 AU

     1975 ET     R. A. (1950) Decl.     Delta     r      m1
     Oct. 15     8 27.91    - 2 49.4    1.933   1.879   10.0
          20     8 31.18    - 6 34.2
          25     8 34.08    -10 42.1    1.741   1.819    9.6
          30     8 36.52    -15 14.7
     Nov.  4     8 38.41    -20 13.1    1.576   1.766    9.3

            m1 = 5.8 + 5 log Delta + 10 log r

The second set of elements gives correctibns of -0m.01, +0'.5 to the
first ephemeris place and -0m.16, +13'.3 to the last one.


COMET SUZUKI-SAIGUSA-MORI (1975k)
     The following precise positions have been communicated:

     1975 UT             R. A. (1950) Decl.        m1    Observer
     Oct.  6.81152    11 11 40.07   +43 36 55.6    7     Suzuki
           7.42604    11 12 10.13   +43 34 32.0          Moore
           7.44826    11 12 11.22   +43 34 29.4            "
           7.49549    11 12 13.72   +43 34 19.1            "
           8.79931    11 13 25.14   +43 28 03.9    7     Shibasaki
           8.81042    11 13 25.61   +43 28 01.3            "
           8.81458    11 13 25.54   +43 28 01.7            "

K. Suzuki (JCPM Oi Station).  Measurer: T. Urata.  Communicated by
   K. Osawa.
E. Moore (Joint Observatory for Cometary Research).  37-cm f/2
   Schmidt camera.  Measurer: E. Tedesco.  Communicated by Tedesco.
H. Shibasaki (Tokyo Astronomical Observatory).  Measurer: H. Kosai.
   Communicated by Osawa.

     The comet is a diffuse object with a central condensation, but
nothing is reported about a tail.  The following parabolic elements,
derived by Z. Sekanina, satisfy the above observations within
3".  Because of a very short arc covered by the observations and
their somewhat unfavorable distribution, the elements and the
resultant ephemeris are rather uncertain.

       T = 1975 Oct. 13.87 ET    Peri. = 150.39
                                 Node  = 215.53    1950.0
       q = 0.8357 AU             Incl. = 118.01

     1975 ET     R. A. (1950) Decl.     Delta     r      m1
     Oct. 13    11 18.70    +42 53.6
          15    11 22.38    +42 25.6    0.598   0.836    7.6
          17    11 27.19    +41 45.6
          19    11 33.60    +40 47.9    0.456   0.841    7.0
          21    11 42.37    +39 21.8
          23    11 54.77    +37 06.9    0.314   0.853    6.3
          25    12 13.15    +33 19.2

               m1 = 9.5 + 5 log Delta + 10 log r

     The elements indicate a possibility of a close approach of the
comet to the earth at the end of October.  If it is so, the comet
might become a naked-eye object for a short period of time in late
October in the northern hemisphere and in early November in the
southern hemisphere.  If the comet develops a tail, there is also
a possibility that the earth might pass through it on or around
October 30.

     P. Maley (Houston, Texas, 13-cm f/5 refractor) reports a total
visual magnitude of 8.2 and a coma 5' in diameter on Oct. 9.46 UT.


1975 October 14                (2850)              Zdenek Sekanina

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