[IAUC] IAUC 9202: C/2011 F1 [25139-2011/04-R1]

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                                                  Circular No. 9202
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU en EPS.HARVARD.EDU           ISSN 0081-0304
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Prepared using the Tamkin Foundation Computer Network


COMET C/2011 F1 (LINEAR)
     An apparently asteroidal object reported by the LINEAR survey
(discovery observation tabulated below) and posted on the Minor
Planet Center's 'NEOCP' webpage has been found by several CCD
astrometrists to show cometary appearance.  H. Sato (Tokyo, Japan)
used a 0.50-m f/6.8 reflector remotely at the Global Rent-a-Scope
(GRAS) Observatory near Mayhill, NM, U.S.A., on Mar. 18.2 and 20.4
UT to find a strongly condensed coma of diameter 8" and total red
mag 18.1.  E. Guido and G. Sostero write that twelve stacked 120-s
images taken remotely on Mar. 18.46-18.47 UT with a GRAS 0.51-m
f/6.9 reflector show a sharp coma nearly 8" in diameter, elongated
toward the southwest; Sostero and Guido also stacked twenty
unfiltered 180-s images obtained remotely on Mar. 18.43-18.49 with
a 0.18-m f/7.3 refractor at the Tzec Maun Observatory (Cloudcroft,
NM, U.S.A.) to find an extremely sharp and condensed coma nearly 10"
in diameter.  P. Birtwhistle (Great Shefford, Berkshire, England,
0.40-m reflector) finds the object to be diffuse with a condensed
coma of diameter 6" and a tail 8" long in p.a. 230 deg on his
images from Mar. 18.8; a similar appearance was noted on Mar. 19.9
and 20.9, the comet having its center of light slightly offset to
the northeast with the southwest boundary being softer on the last
date, with the 8" extension in p.a. 240 deg.  Roger Banks
(Montgomery, Powys, U.K., 0.4-m astrograph, Mar. 19.1) finds the
object to be diffuse with diameter 4".6 and extended for 1".3 in
p.a. 220 deg.  R. Ligustri (Udine, Italy; remotely with a GRAS
0.50-m reflector, Mar. 19.45-19.46) finds a faint coma elongated
in p.a. 210 deg.  Luca Buzzi (Varese, Italy, 0.38-m f/6.8 reflector,
Mar. 20.83-20.85) notes that stacked images taken in good seeing
and in moonlight show a coma that is clearly elongated in p.a.
about 250 deg.  L. Buzzi, P. Concari, S. Foglia, G. Galli, and M.
Tombelli find a round coma of diameter 15" and red mag 17.0-17.2 on
stacked images obtained remotely with a 0.18-m f/7.3 refractor at
the Tzec Maun Observatory on Mar. 21.3-21.4.

     2011 UT             R.A. (2000) Decl.       Mag.   Observer
     Mar. 17.28470   12 20 47.92   +67 07 40.2   18.3   LINEAR

The available astrometry, the following preliminary parabolic
orbital elements by G. V. Williams, and an ephemeris appear on MPEC
2011-F15.

     T = 2013 Jan. 21.6608 TT         Peri. = 197.2328
                                      Node  =  85.2212  2000.0
     q = 1.617545 AU                  Incl. =  56.8577

                      (C) Copyright 2011 CBAT
2011 March 21                  (9202)            Daniel W. E. Green