Electronic Telegram No. 4291
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 N4 (MASTER)
     An apparently asteroidal object that was found on images taken by a team
including O. Gress, V. Lipunov, and eleven others with the MASTER 0.4-m f/2.5
reflector at Tenerife (discovery observations tabulated below) has been found
to show cometary appearance on images taken by CCD astrometrists elsewhere.

     2016 UT             R.A. (2000) Decl.       Mag.   Observer
     July 15.14549    0 30 17.38   -18 16 42.3   16.8   MASTER
          15.15631    0 30 17.29   -18 16 41.7   16.8     "
          15.16426    0 30 17.16   -18 16 41.0   16.7     "
          16.13479    0 30 03.51   -18 15 48.9   16.7     "
          16.15104    0 30 03.27   -18 15 49.0   16.9     "
          16.16542    0 30 03.04   -18 15 48.1   16.9     "
          16.17978    0 30 02.82   -18 15 47.1   16.8     "
          16.19580    0 30 02.59   -18 15 46.5   16.8     "

After the object was posted on the Minor Planet Center's NEOCP webpage, H.
Sato, Tokyo, Japan, found the object to show a strongly condensed, round coma
15" in diameter with no tail on four stacked 60-s exposures taken on July
16.48 UT with an iTelescope 0.61-m f/6.5 astrograph (+ luminance filter)
located at the Sierra Remote Observatory near Auberry, CA, USA; the w-band
magnitude was 16.5 as measured within a circular aperture of radius 7".5.
L. Buzzi, Varese, Italy, writes that stacked images taken with a 0.60-m f/4.6
reflector on July 17.1 show that the object has a fuzzy appearance (softer
respect to stars), with a round coma 15" wide and a possible tail 60" long in
p.a. 190 deg.  Twenty stacked 60-s images taken by C. Jacques, E. Pimentel,
and J. Barros with a 0.45-m f/2.9 reflector at the SONEAR Observatory at
Oliveira, Brazil, on July 17.3 show a condensed coma 15" in diameter with
red mag 16.9, elongated 23" toward p.a. 212 deg.  Sixty co-added 20-s images
taken by R. Holmes (Ashmore, IL, USA) with a 0.61-m f/4.5 astrograph on
July 17.4 show a round coma 9".2 in diameter and a diffuse tail 16".4 long
in p.a. 229 deg (measurers listed as S. Foglia, L. Buzzi, T. Linder, and
Holmes).
     The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams, and an ephemeris appear on MPEC 2016-O266.

     T = 2015 July 17.3090 TT         Peri. = 266.7665
                                      Node  =   0.4239  2000.0
     q = 3.028161 AU                  Incl. =  53.9423


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

                         (C) Copyright 2016 CBAT
2016 July 18                     (CBET 4291)              Daniel W. E. Green