Electronic Telegram No. 3973
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 R4 (GIBBS)
     A. R. Gibbs reports his discovery of a comet on CCD images obtained with
the Catalina Sky Survey's 0.68-m Schmidt telescope (discovery observations
tabulated below); four co-added 30-s exposures show a diffuse coma 15" x 20"
in size, elongated in the direction of motion and becoming a broad tail 20"
long in p.a. 320 deg.

     2014 UT             R.A. (2000) Decl.       Mag.   Observer
     Sept.14.47552    7 46 52.13   +32 41 40.6   16.5   Gibbs
          14.48256    7 46 53.09   +32 41 33.2   16.5     "
          14.48959    7 46 54.04   +32 41 24.1   16.5     "
          14.49661    7 46 54.97   +32 41 14.7   16.5     "

After the object was posted on the Minor Planet Center's NEOCP and PCCP
webpages, other CCD astrometrists have also commented on the object's cometary
appearance.  T. Prystavski and A. Novichonok identified three pre-discovery
images of the comet taken via 120-s exposures on Aug. 21.0 UT by G. Borisov
with a 0.3-m f/1.5 astrograph at the MARGO Observatory at Nauchnij, Russia,
showing a faint and very diffuse coma (total mag near 15.3) approximately 1'.1
in diameter, slightly condensed but with no tail visible.  L. Buzzi reports
that fifty-two stacked 15-s images taken by R. Holmes (Ashmore, IL, USA;
0.61-m f/4 astrograph) on Sept. 15.4 in bright moonlight show a non-stellar
central condensation surrounded by a diffuse 20" coma.  H. Sato (Tokyo, Japan)
stacked eight 60-s exposures obtained with an iTelescope 0.61-m f/6.5
astrograph (+ luminance filter) located at Auberry, CA, USA, to find a diffuse
outer coma 40" in diameter and a fan-like tail 1' long spanning p.a. 290-350
degrees; the w-band magnitudes were 15.7 and 17.9 as measured within circular
apertures of radii 20".2 and 3".8, respectively.  E. Bryssinck (Kruibeke,
Belgium; 0.4-m f/3.8 astrograph; Sept. 17.16) finds a diffuse coma of size
19" and a hint of a tail 28" long towards p.a. 244 degrees.
     The available astrometry, the following elliptical orbital elements by
G. V. Williams, and an ephemeris appear on MPEC 2014-S09.

                    Epoch = 2014 Oct. 30.0 TT
     T = 2014 Oct. 22.2194 TT         Peri. = 181.2722
     e = 0.955813                     Node  = 279.2576  2000.0
     q = 1.804115 AU                  Incl. =  42.5173


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2014 CBAT
2014 September 17                (CBET 3973)              Daniel W. E. Green