Electronic Telegram No. 3046
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/2012 E1 (HILL)
     R. E. Hill reports his discovery of a comet (discovery observations
tabulated below) on CCD images taken with the Mount Lemmon 1.5-m reflector,
the object reported as then having a small, condensed nuclear condensation
with a small coma of diameter about 6" with a fan-shaped tail about 10" long
in p.a. 160 deg in four co-added 30-s exposures in 2"-3" seeing; similar
co-added follow-up images taken during Mar. 2.50-2.52 UT show the fan-shaped
tail as being 12"-15" long.  Hill's four co-added 40-s images taken in 3"-4"
seeing on Mar. 3.5 show a 10"-12" fan-shaped tail in p.a. about 170 deg;
his images from Mar. 4.5 again show a coma about 5"-7" across and the same
dimensions for the fan-shaped tail as on the previous night.  After posting
on the Minor Planet Center's NEOCP webpage, other CCD astrometrists have
also commented on the object's cometary apperance.  H. Sato (Tokyo, Japan)
used a 0.43-m f/6.8 astrograph (+ f/4.5 focal reducer) at the RAS Observatory
near Nerpio, Spain, yielding images on Mar. 4.2 that show a 16" coma with a
20" tail toward p.a. 160 deg; his additional stacked images taken on Mar.
5.51 with a 0.51-m f/6.8 astrograph (+ f/4.5 focal reducer) at the RAS
Observatory near Mayhill, NM, U.S.A. show a 10" coma of mag V = 19.6 in a
circular aperture of radius 4".9 that was elongated toward p.a. 165-210 deg
(but with no obvious tail).  Stacked images taken by R. Holmes (Ashmore, IL,
USA) with a 0.81-m f/4 astrograph (and measured by T. Vorobjov, L. Buzzi, H.
Devore, and S. Foglia) on Mar. 4.5 show a diffuse, round coma 10" in diameter.
R-band images taken by W. H. Ryan and E. V. Ryan with the Magdalena Ridge
Observatory 2.4-m f/8.9 reflector on Mar. 5.4 show a faint tail at p.a. about
180 deg.

     2012 UT             R.A. (2000) Decl.       Mag.   Observer
     Mar.  2.47514   16 59 23.38   +28 28 34.2   19.6   Hill
           2.48036   16 59 23.35   +28 28 37.3   19.6     "
           2.48560   16 59 23.31   +28 28 40.0   19.7     "
           2.49074   16 59 23.24   +28 28 42.9   19.8     "

The available astrometry, the following preliminary parabolic orbital elements
by G. V. Williams, and an ephemeris appear on MPEC 2012-E39.

     T = 2011 June 19.9736 TT         Peri. =  47.8459
                                      Node  = 286.2284  2000.0
     q = 7.481484 AU                  Incl. = 122.5082


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

                         (C) Copyright 2012 CBAT
2012 March 5                     (CBET 3046)              Daniel W. E. Green