Electronic Telegram No. 4328
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 T1 (MATHENY)
     Rose G. Matheny reports the discovery of a comet with a compact, round
coma approximately 6"-8" in diameter on CCD images obtained in a sky with poor
transparency on Oct. 6 with the 1.5-m reflector in the course of the Mount
Lemmon Survey (discovery observations tabulated below); four co-added 30-s
exposures show a fan-shaped tail toward p.a. 55 deg.  Follow-up exposures
taken by Matheny on Oct. 11.1 UT show a faint broad tail towards p.a. 90-105
deg; the magnitude was then measured to be 18.3-18.4.

     2016 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct.  6.09330   18 35 12.35   +32 48 12.7   18.4   Matheny
           6.09759   18 35 12.05   +32 48 04.2   18.4     "
           6.10188   18 35 11.74   +32 47 55.9   18.1     "
           6.10617   18 35 11.47   +32 47 47.7   18.2     "
           6.14426   18 35 08.96   +32 46 32.3   18.3     "
           6.14704   18 35 08.73   +32 46 27.0   18.4     "
           6.14993   18 35 08.49   +32 46 21.6   18.5     "
           6.15359   18 35 08.14   +32 46 13.8            "

After the comet was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists have also commented on the cometary appearance.  V-band
images taken on Oct. 6.2 UT by W. H. Ryan and E. V. Ryan with the Magdalena
Ridge Observatory 2.4-m f/8.9 reflector show a "fuzzy" appearance with a wide
coma/tail at p.a. about 90 degrees.  H. Sato, Tokyo, Japan, writes that
fifteen stacked 60-s exposures taken on Oct. 7.8 with an iTelescope 0.43-m
f/6.8 astrograph (+ luminance filter) at Nerpio, Spain, shows a strongly
condensed coma 6" in diameter and no tail; the w-band magnitude was 17.7 as
measured within a circular aperture of radius 3".8.  R. Weryk, Institute for
Astronomy, University of Hawaii, notes that four i-band exposures taken with
the 1.8-m Pan-STARRS1 telescope at Haleakala on Oct. 8.3 shows a short 3"
tail towards the south; the coma appears tiny (FWHM around 1".3, vs. 1".1
for nearby stars), with a much fainter magnitude given (19.9-20.1).  Stacked
images obtained by L. Buzzi, Varese, Italy, with a 0.60-m f/4.64 reflector
on Oct. 11.8 show a strong central condensation and a faint coma extended
toward the southeast; the red magnitude was measured to be 19.3.
     The available astrometry, the following preliminary parabolic orbital
elements by G. V. Williams (from 93 observations spanning Oct. 6-11), and an
ephemeris appear on MPEC 2016-T117.

     T = 2017 Jan. 30.5997 TT         Peri. = 136.6277
                                      Node  =  56.3552  2000.0
     q = 2.315639 AU                  Incl. = 129.7776


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

                         (C) Copyright 2016 CBAT
2016 October 11                  (CBET 4328)              Daniel W. E. Green