Electronic Telegram No. 3367
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 C/2012 Y3 (McNAUGHT)
     R. H. McNaught reports his discovery of a moderately condensed comet with
a 0'.4 coma extended toward the northeast on CCD images obtained with the
0.5-m Uppsala Schmidt telescope at Siding Spring (discovery observations
tabulated below with total magnitudes).  After posting on the Minor Planet
Center's NEOCP webpage, other CCD astrometrists have also commented on the
object's cometary appearance.  T. Linder and R. Holmes found a round 1' coma
on co-added images taken with a 0.41-m f/11 Ritchey-Chretien telescope at
Cerro Tololo on 2012 Dec. 31.1 UT.  C. Jacques and E. Pimentel (Belo Horizonte,
Brazil), with J. Barros, obtained images remotely with an "itelescope.net"
0.50-m f/6.8 astrograph at Siding Spring on Dec. 31.68 that show a condensed
coma 30" in diameter and no evidence of a tail.  M. Masek, Liberec, Czech
Republic, writes that observations obtained by J. Cerny, J. Ebr, M. Prouza,
P. Kubanek, M. Jelinek, and himself on 2013 Jan. 1.05-1.06 with a 0.3-m f/10
reflector show a strong central condensation of diameter 8" with a diffuse
coma of diameter 21".  E. Guido, Castellammare di Stabia, Italy, notes that
nineteen stacked 30-s unfiltered exposures taken by N. Howes and himself on
Jan. 1.5 with an "iTelescope.Net" 0.32-m f/9.0 Ritchey-Chretien telescope at
Siding Spring show a coma about 10" in diameter with a fan-shaped tail
elongated in p.a. 95 deg.

     2012 UT             R.A. (2000) Decl.       Mag.   Observer
     Dec. 30.57879    5 36 59.79   -59 48 26.6   15.2   McNaught
          30.58320    5 36 59.29   -59 48 19.7   15.1     "
          30.60486    5 36 57.08   -59 47 42.7   15.4     "
          30.60919    5 36 56.70   -59 47 35.9   15.3     "
          30.61778    5 36 55.70   -59 47 21.8   15.3     "
          30.62229    5 36 55.24   -59 47 13.1   15.4     "
          30.73150    5 36 43.97   -59 44 08.5   15.4     "
          30.73609    5 36 43.49   -59 44 00.6   15.4     "
          30.73926    5 36 43.20   -59 43 55.1   15.3     "

The available astrometry, the following preliminary parabolic orbital elements
by G. V. Williams, and an ephemeris appear on MPEC 2013-A03.

     T = 2012 Aug. 26.5911 TT         Peri. = 236.1539
                                      Node  = 121.6933  2000.0
     q = 1.781719 AU                  Incl. =  73.9022


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 January 1                   (CBET 3367)              Daniel W. E. Green