Electronic Telegram No. 4239
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)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET C/2016 A6 (PANSTARRS)
     R. Weryk and R. Wainscoat report the discovery of an apparent comet in
four w-band exposures taken on Jan. 13 UT with the 1.8-m Pan-STARRS1 telescope
on Haleakala (discovery observations tabulated below); the object has an
extended point-spread function (1".8) compared to adjacent stars (1".1-1".3;
variable seeing) in stacked images, and there is a hint of an extension
(possible tail) to the north.

     2016 UT             R.A. (2000) Decl.       Mag.
     Jan. 13.44434    9 46 30.61   +33 40 44.1   21.0
          13.45507    9 46 27.69   +33 40 43.1   21.1
          13.46582    9 46 24.77   +33 40 41.8   21.2

After the object was posted on the Minor Planet Center's PCCP webpage, CCD
astometrists elsewhere have also noted the object's cometary appearance.
V-band images taken by W. H. Ryan and E. V. Ryan with the Magdalena Ridge
Observatory 2.4-m f/8.9 reflector on Jan. 14.3 UT show a faint, wide tail in
p.a. about 45 deg; their measured magnitude was 20.5-21.0.  H. Sato, Tokyo,
Japan, reports that twenty stacked 60-s exposures taken remotely with an
iTelescope 0.43-m f/6.8 astrograph (+ luminance filter) near Mayhill, NM,
USA, on Jan. 14.5 show a strongly condensed coma 6" in diameter with no
tail; the w-band magnitude was 20.5 as measured within a circular aperture
of radius 5".7.  K. Sarneczky, Konkoly Observatory, writes that nine stacked
60-s exposures taken on Jan. 18.1 with the 0.60-m Schmidt telescope at
Piszkesteto Observatory show a diffuse coma 10" in diamater with no tail.
     The available astrometry (spanning Jan. 13-18), the following preliminary
parabolic orbital elements by G. V. Williams, and an ephemeris appear on MPEC
2016-B34.

     T = 2015 Nov.  6.9050 TT         Peri. = 141.4491
                                      Node  = 300.2329  2000.0
     q = 2.417856 AU                  Incl. = 121.0198


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2016 CBAT
2016 January 20                  (CBET 4239)              Daniel W. E. Green