Electronic Telegram No. 3186
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET P/2012 O1 (McNAUGHT)
     R. H. McNaught reports his discovery of a comet that is moderately to
very diffuse with a 0'.3-diameter coma that is slightly extended to the west
on CCD images obtained with the 0.5-m Uppsala Schmidt telescope at Siding
Spring (discovery observations tabulated below).  His follow-up images on July
19.7-19.8 UT show a coma and condensation of total mag 18.6-18.8 extended in
p.a. 240 deg.  After posting on the Minor Planet Center's NEOCP webpage,
other CCD astrometrists have also commented on the object's cometary
appearance.  J. V. Scotti writes that images taken with the Spacewatch 1.8-m
f/2.7 reflector at Kitt Peak on July 19.47 show the object to be slightly
diffuse with a coma diameter of 7" and a faint tail extending 0'.10 in p.a.
241 deg; his six stacked images with the same telescope on July 20.5 reveal
the comet to be slightly diffuse with a coma diameter of 6" and a tail
extending 0'.13 in p.a. 233 deg.  G. Hug (Scranton, KS, U.S.A., 0.56-m
reflector) found the object to be somewhat diffuse on July 20.4.  Stacked
images taken by R. Holmes (Ashmore, IL, USA; 0.61-m f/4 astrograph; measured
by T. Vorobjov, L. Buzzi, and S. Foglia) on July 21.4 show a diffuse coma of
diameter 10" and a hint of a tail in p.a. 265 degrees.

     2012 UT             R.A. (2000) Decl.       Mag.   Observer
     July 18.74126    0 57 37.31   - 7 18 06.9   18.9   McNaught
          18.75644    0 57 39.58   - 7 18 06.1   18.7     "
          18.77165    0 57 41.93   - 7 18 06.7   18.3     "
          18.78683    0 57 44.23   - 7 18 06.9   18.5     "

The available astrometry, the following preliminary elliptical orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2012-O16.

     T = 2012 July 23.2492 TT         Peri. = 221.2879
     e = 0.649036                     Node  = 112.4319  2000.0
     q = 1.522803 AU                  Incl. =  11.7544
       a =  4.338916 AU    n = 0.1090516    P =   9.04 years


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 July 21                     (CBET 3186)              Daniel W. E. Green