Electronic Telegram No. 3244
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 S3 (PANSTARRS)
     Richard Wainscoat, Peter Veres, and Bryce Bolin report the discovery of
a comet that appears non-stellar in each of the two i-band and two r-band
discovery exposures that were obtained by the Pan-STARRS1 telescope (discovery
observations tabulated below); the full-width-at-half-maximum of star images
in each exposure was 0".85-1".0, while the comet has a FWHM of approximately
1".5.  After posting on the Minor Planet Center's NEOCP webpage, other CCD
astrometrists have commented on the object's cometary appearance.  P.
Birtwhistle (Great Shefford, Berkshire, England; 0.40-m f/6 Schmidt-Cassegrain
reflector) found the comet to have a diffuse, condensed coma 9" in diameter
with no tail visible on Sept. 29.02-29.06 UT; it showed a similar appearance
on Sept. 29.8, with an 8" coma.  Images taken by J. D. Armstrong and M.
Micheli with 2.0-m f/10 "Faulkes Telescope North" at Haleakala on Sept. 30.25-
30.28 show a definitely cometary appearance (FWHM of coma about 1".5 in 1".1
seeing, with an elongation of about 1" toward p.a. 60 deg in 640 s of total
exposure time).  H. Sato (Tokyo, Japan; images taken remotely with a 0.43-m
f/6.8 astrograph at the RAS Observatory near Mayhill, NM, USA) writes that
images taken on Oct. 2.1 show no obvious coma but a faint tail 10" long
toward p.a. 45 degrees; he measured a total V-band magnitude of 19.2 within a
circular aperture of radius 5".7.

     2012 UT             R.A. (2000) Decl.       Mag.
     Sept.27.29884   19 55 06.77   +67 13 27.6   20.2
          27.31297   19 55 05.81   +67 13 09.9   20.1
          27.32424   19 55 05.05   +67 12 55.7   20.2

The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2012-T03.

     T = 2013 Aug. 31.6616 TT         Peri. = 183.2119
                                      Node  = 121.1350  2000.0
     q = 2.328751 AU                  Incl. = 112.9389


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 October 2                   (CBET 3244)              Daniel W. E. Green