Electronic Telegram No. 3988
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/2014 S1 (PANSTARRS)
     R. Wainscoat and L. Denneau report the discovery of a comet in four
w-band CCD exposures taken on Sept. 19 with the 1.8-m Pan-STARRS1 telescope at
Haleakala (discovery observations tabulated below), the object showing a
distinctly extended appearance and a broad, diffuse low-surface-brightness
tail extending approximately 10" in p.a. approximately 35 degrees.  M. Micheli
writes that Wainscoat obtained three follow-up 60-s r-band exposures of the
comet using the 3.6-m Canada-France-Hawaii Telescope on Sept. 22.5 UT (queue
observer P. Forshay); analysis of these images by Micheli and Wainscoat
confirms the cometary activity, as the object displays an evident broad,
fan-shaped tail approximately 8" long in p.a. about 90 deg and has a coma with
a condensed core.

     2014 UT             R.A. (2000) Decl.       Mag.
     Sept.19.56326    3 09 49.55   -29 28 20.8   21.3
          19.57446    3 09 49.14   -29 28 23.8   21.3
          19.58568    3 09 48.73   -29 28 26.6   21.4
          19.59688    3 09 48.31   -29 28 29.6   21.3

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 ten stacked 60-s exposures taken with an
iTelescope 0.70-m f/6.6 astrograph (+ luminance filter) at Siding spring on
Sept. 20.6 UT show a diffuse and moderately condensed coma 8" in diameter
(with w-band magnitude 20.1 as measured within a circular aperture of radius
4".4) and a faint tail 20" long toward p.a. 80 degrees.  T. Lister writes that
nine stacked 250-s R-band exposures taken with a 1.0-m f/8 Ritchey-Chretien
reflector at Cerro Tololo on Sept. 20.34-20.37 show a coma of diameter about
8" with a tail about 60" long.
     The available astrometry, the following very preliminary parabolic
orbital elements by G. V. Williams, and an ephemeris appear on MPEC 2014-S82.

     T = 2015 May  17.7408 TT         Peri. = 322.7639
                                      Node  = 353.7204  2000.0
     q = 8.169335 AU                  Incl. = 123.1106


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 September 24                (CBET 3988)              Daniel W. E. Green