651007Announcement11_p1

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                    THE ROYAL ASTRONOMICAL SOCIETY OF CANADA

                            COMET AND NOVA SECTION
                                                              Announcement #11
COMET IKEYA-SEKI (1965f)

This comet, discovered on September 18, is expected to become very bright, and
may be one of the brightest of the century. The following is a modification of
the ephemeris supplied by Michael McCants. Note that it differs from the
ephemeris listed on Announcement #10.

          1965   R.A.1950    Decl.    Mag. Angle   40 N      50 N
        00h U.T.                           from
                  h  m        °   '        sun          Rises
       Oct.  9   10 45.3    -14 07    3.8   33      4.4       4.7
            12   11 17.1    -14 43    2.8   28      4.8       5.2
            13   11 29.0    -14 48    2.4   26      4.9       5.3
            14   11 41.7    -14 50    2.0   24      5.1       5.5
            15   11 55.1    -14 48    1.5   21      5.2       5.6
            16   12 09.3    -14 43    1.0   19      5.4       5.8
            17   12 24.2    -14 37    0.4   16      5.6       6.0
            18   12 40.2    -14 12   -0.5   13      5.8       6.1
            19   12 57.4    -13 40   -1.7   10      6.0       6.3
            20   13 16.0    -12 55   -3.2    6      6.2       6.5
            21   13 38.4    -11 20   -8.8    1      6.3       6.5
            22   13 24.9    -10 53   -4.3    5      5.8       6.1
            23   13 13.4    -11 48   -3.0    9      5.7       5.9
            24   13 04.7    -12 36   -1.7   12      5.5       5.8
            25   12 55.3    -13 21   -0.5   15      5.4       5.7
            26   12 48.2    -14 12    0.6   18      5.2       5.6
            27   12 42.9    -14 58    1.6   20      5.0       5.5
       Nov.  1   12 17.7    -18 27    3.4   30      4.6       5.0
             6   11 56.9    -21 40    4.5   39      4.2       4.7
            16   11 18.5    -27 41    6.0   56      3.3       4.0
            26   10 36.9    -33 04    6.9   72      2.6       3.4
       Dec.  6   09 46.6    -37 11    7.6   88      1.3       low
            16   08 50.2    -39 12    8.3  102      0.2
            26   07 53.9    -38 33    8.9  114     22.4


This comet is related to the Great Sun Grazing Comet of 1882 and its family.
Perihelion occurs on October 21 when the comet passes less than 200,000 miles
from the surface of the sun. In fact, ate set of orbital elements indicates
that the perihelion distance is below the solar surface, so this ephemeris is
doubtful after October 21.

The magnitude is based on:
       Mag. 6.2 + 5log (dist. from earth) + 10log (dist. from sun)
but the actual magnitude could be somewhat different from the listed value. It
appears, however, that the comet will be brighter than Venus when near the sun.

The undersigned has determined the time of "Comet-rise" for 40° and 50° N lati-
tude, and they are listed to the nearest tenth of an hour.  Interpolate or
extrapolate for other latitudes. These are local mean times. To convert to
standard times, see page 12 of the OBSERVER'S HANDBOOK.