Electronic Telegram No. 3485
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/2013 H1 (LA SAGRA)
     An object reported initially by J. Nomen as a possible comet from images
taken on Apr. 19 in the course of the "La Sagra Sky Survey" with a 0.45-m
f/2.8 reflector at La Sagra, Spain (discovery observations tabulated below),
and posted on the Minor Planet Center's NEOCP webpage, has been conclusively
shown subsequently to show cometary appearance from images obtained later by
Nomen (on Apr. 21.04-21.06 UT, showing the object to be diffuse and elongated
with a tail about 16" long toward p.a. 240 deg) and by CCD astrometrists
elsewhere.  J. Lacruz (La Canada, Spain; 0.40-m Ritchey-Chretien reflector;
Apr. 19.9 UT) finds a compact nuclear condensation and a diffuse coma
extending 20" from p.a. 225 to 290 deg.  H. Sato (Tokyo, Japan; remotely with
a 0.43-m f/6.8 astrograph at the iTelescope Observatory near Mayhill, NM,
U.S.A.; six stacked 120-s exposures from Apr. 20.3) reports a strongly
condensed coma 15" in diameter with V-band magnitude 17.9 as measured within
a circular aperture of radius 9".5.  Sixty stacked 20-s images taken on Apr.
20.3 by R. Holmes (Ashmore, IL, USA; 0.61-m f/4 astrograph; measured by T.
Vorobjov, L. Buzzi, and S. Foglia) show a coma 8" wide and a tail 20" long in
p.a. 240 deg.  Erik Bryssinck, Kruibeke, Belgium, writes that his five
co-added 180-s images taken on Apr. 21.01 remotely with a 0.43-m f/6.8
reflector of the iTelescope network at Nerpio, Spain, show a coma of diameter
about 10" with a tail about 18" long to the west (p.a. 272 degrees); his
follow-up co-added images taken with an iTelescope 0.51-m f/4.5 astrograph
near Mayhill on Apr. 21.3 shows a 12" coma with a hint of a tail toward the
southwest (p.a. 245 deg), while similar images with his own backyard 0.4-m
f/3.8 astrograph on Apr. 22.06 with a luminance filter shows a similar
appearance (though the tail p.a. was measured as p.a. 258 deg).  J. G. Ries
(McDonald Observatory, 2.1-m reflector + i-band filter; Apr. 21.4) notes a
tail approximately 10" long toward the southwest.

     2013 UT             R.A. (2000) Decl.       Mag.
     Apr. 19.10802   15 08 33.13   +17 00 56.7   17.7
          19.11773   15 08 32.82   +17 00 55.0   17.8
          19.12745   15 08 32.48   +17 00 52.5   17.8

The available astrometry, the following preliminary parabolic orbital
elements, and an ephemeris appear on MPEC 2013-H27.

     T = 2013 June  1.3726 TT         Peri. = 141.5131
                                      Node  =  84.2059  2000.0
     q = 2.622218 AU                  Incl. =  27.3289


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

                         (C) Copyright 2013 CBAT
2013 April 22                    (CBET 3485)              Daniel W. E. Green