[IAUC] IAUC 9172: P/2010 T1; 103P [25139-2011/04-R1]

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                                                  Circular No. 9172
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU en EPS.HARVARD.EDU           ISSN 0081-0304
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COMET P/2010 T1 (McNAUGHT)
     R. H. McNaught reports his discovery of a diffuse comet on CCD
images obtained with the 0.5-m Uppsala Schmidt telescope (discovery
observation tabulated below, obtained in poor seeing).  In improved
seeing on Oct. 5.4, McNaught found the diffuse coma to have a
diameter of about 12".  Following posting on the 'NEOCP' webpage
and an identification of the object by B. G. Marsden in Uppsala
Schmidt astrometry from Sept. 11.5 UT, McNaught re-examined those
images and noted the comet to be similar in appearance (comet's
image about 1".5 larger than images of stars of similar brightness).
G. Sostero, Povoletto, Italy, reports that sixteen stacked
unfiltered CCD exposures taken by E. Guido, L. Donato, V. Gonano,
and himself remotedly with a 0.15-m refractor located at the Tzec
Maun Observatory (near Moorook, Australia) on Oct. 5.6 show a coma
nearly 7" in diameter with a central condensation and a broad, fan-
shaped tail about 12" long toward p.a. 310 deg.  S. Foglia writes
that CCD images obtained remotely on Oct. 5.6 by L. Buzzi, P.
Concari, G. Galli, M. Tombelli, and himself with a 0.18-m reflector
(also at the Tzec Maun Observatory) show the object diffuse to be
diffuse.  H. Sato (Ota-ku, Tokyo, Japan) notes that his CCD images
obtained remotely with a 0.30-m reflector from the RAS Observatory
(also near Moorook) on Oct. 5.7 show a 10" coma with no tail.

     2010 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct.  4.56629   22 47 00.76   -34 37 39.3   18.8   McNaught

The available astrometry, the following preliminary elliptical
orbital elements by Marsden, and an ephemeris appear on MPEC
2010-T27.

     T = 2010 Nov. 24.294 TT          Peri. = 226.899
     e = 0.32329                      Node  = 129.708   2000.0
     q = 3.18597 AU                   Incl. =  32.148
       a =  4.70800 AU     n = 0.096483     P =  10.22 years


COMET 103P/HARTLEY
     Visual total-magnitude and coma-diameter estimates:  Sept.
8.90 UT, 9.5, 7' (B. H. Granslo, Malm, Norway, 0.05-m refractor);
15.00, 8.5, 15' (J. J. Gonzalez, Leon, Spain, 10x50 binoculars);
29.82, 7.7, 15' (G. Pappa, Mascalucia, Italy, 12x50 binoculars);
Oct. 2.86, 6.4, 25' (J. J. Gonzalez, Cantabria, Spain, 4x30
monocular); 5.21, 7.2, 24' (C. S. Morris, Fillmore, CA, U.S.A.,
10x50 binoculars).

                      (C) Copyright 2010 CBAT
2010 October 5                 (9172)            Daniel W. E. Green