Electronic Telegram No. 4256
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
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Prepared using the Tamkin Foundation Computer Network


COMET C/2016 C1 (PANSTARRS)
     R. Wainscoat and R. Weryk report the discovery of an apparent comet in
four w-band exposures taken on Feb. 12.5 UT with the 1.8-m Pan-STARRS1
telescope on Haleakala (discovery observations tabulated below); the object
has a soft nuclear condensation (FWHM = 2".5, compared to adjacent stars
with FWHM = 1".0) and a broad tail extending for approximately 15" to the
east.

     2016 UT             R.A. (2000) Decl.       Mag.
     Feb. 12.49594   10 21 13.70   -20 54 18.1   19.9
          12.50670   10 21 13.50   -20 54 15.7   20.0
          12.51744   10 21 13.34   -20 54 13.8   19.6
          12.52823   10 21 13.14   -20 54 11.3   19.8

Wainscoat obtained follow-up images with the Canada-France-Hawaii Telescope
at Mauna Kea on Feb. 13.38 UT with a w-band filter, in which the object has a
soft appearance of mag 18.4 with a broad tail extending for approximately 30"
to the east.  After the object was posted on the Minor Planet Center's PCCP
webpage, other CCD astrometrists have also commented on the object's cometary
appearance.  H. Sato, Tokyo, Japan, writes that five stacked 60-s exposures
taken with a 0.51-m f/6.8 astrograph (+ luminance filter) at Siding Spring on
Feb. 13.5 show the object to be strongly condensed with a round coma 12" in
diameter and no tail; the w-band magnitude was 17.7 as measured within a
circular aperture of radius 6".5.  Images taken on Feb. 13.9 by T. Lister, S.
Greenstreet, and E. Gomez with a 1.0-m f/8 Ritchey-Chretien reflector
at Sutherland, South Africa, show a coma of diameter about 6".5 with an
extension out to about 11".
     The available astrometry (spanning Feb. 12-13), the following very
preliminary parabolic orbital elements by G. V. Williams, and an ephemeris
appear on MPEC 2016-C175.

     T = 2016 Jan.  5.5347 TT         Peri. = 326.4148
                                      Node  = 181.4226  2000.0
     q = 8.524482 AU                  Incl. =  56.7239


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2016 CBAT
2016 February 14                 (CBET 4256)              Daniel W. E. Green