Electronic Telegram No. 2790
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/2011 Q1 (PANSTARRS)
     Richard Wainscoat, Marco Micheli, Henry Hsieh, and Larry Denneau report
the discovery of an apparent comet on images taken with the 1.8-m "Pan-STARRS
1" telescope at Haleakala (discovery observation tabulated below); Wainscoat
notes that the object has a distinctly extended point-spread function (PSF),
with a core having FWHM approximately 1".2 and nearby stars having a PSF of
approximately 1".0 arcsec.  Shinsuke Abe, Institute of Astronomy, National
Central University (Jhongli, Taoyuan, Taiwan) writes that follow-up CCD
frames taken by H. Y. Hsiao and himself with a 1.0-m f/8 Cassegrain reflector
at Lulin Observatory on Aug. 21.7 UT also show an apparent cometary
appearance.  After posting on the Minor Planet Center's NEOCP webpage, other
CCD astrometrists have also noted cometary appearance.  L. Buzzi, Varese,
Italy, notes that stacked images taken around Aug. 21.98-22.00 UT with a
0.60-m f/4.6 reflector show a 8" compact coma (red mag 18.7) with a FWHM
around 30 percent larger than that of nearby stars; a 30" tail is seen
around p.a. 340 deg, but it is difficult to estimate due to background
nebulosity in the area.  Stacked CCD images taken around Aug. 22.1 by
R. Holmes (Ashmore, IL, USA; 0.61-m f/4.0 astrograph; measured by S. Foglia,
L. Buzzi, and T. Vorobjov) show the object to have an elongated coma of size
6" x 12" and mag 19.1-19.3, elongated toward p.a. 350 deg, where there is
a 20"-long tail.

     2011 UT             R.A. (2000) Decl.       Mag.
     Aug. 20.44054   20 48 02.41   +30 21 49.2   20.6

The available astrometry, the following very preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2011-Q12.

     T = 2012 Oct. 25.931 TT          Peri. = 213.600
                                      Node  = 164.968   2000.0
     q = 3.19973 AU                   Incl. =  67.584


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2011 CBAT
2011 August 22                   (CBET 2790)              Daniel W. E. Green