[IAUC] IAUC 9033: C/2009 F5 [25139-2009/08-R1]

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                                                  Circular No. 9033
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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COMET C/2009 F5 (McNAUGHT)
     R. H. McNaught reports his discovery of another comet on CCD
survey images obtained with the 0.5-m Uppsala Schmidt reflector at
Siding Spring (discovery observation tabulated below), the object
showing a 0'.6 coma that appears extended toward the west, though
the full extent and existence of a tail is diffult to judge due to
the crowded star field.  Following posting on the Minor Planet
Center's 'NEOCP' webpage, other CCD astrometrists have also
commented on the object's cometary appearance.  J. E. McGaha
(Tucson, AZ, U.S.A., 0.36-m f/10 Schmidt-Cassegrain reflector, Mar.
21.4 UT) relates that five stacked 60-s exposures show a bright 6"
nuclear condensation surrounded by a faint round 16" coma and no
tail.  Three stacked 60-s images taken with the Mt. John 1.0-m
f/7.7 reflector by A. C. Gilmore on Mar. 21.5 (measured by P. M.
Kilmartin) show a circular coma of diameter 13" with a stellar
condensation at its center but no tail; however, three stacked
120-s images taken on Mar. 22.4 at Mt. John show a circular 20"
coma with the central starlike condensation and a possible faint,
broad tail 90" long in p.a. about 230 deg.  E. Guido (Castellammare
di Stabia, Italy) writes that twenty co-added, unfiltered 120-s CCD
exposures taken remotely with 0.25-m f/3.4 reflector near Mayhill,
NM, U.S.A., by G. Sostero, P. Camilleri, and himself on Mar. 22.4
reveal a coma diameter of about 30" and a strong central
condensation.  J. W. Young (Table Mountain 0.61-m f/16 Cassegrain
reflector, Mar. 22.4) reports that his exposures taken at low
altitude show a fuzzy appearance with a size around 10"-12".  R.
Ligustri (Talmassons, Udine, Italy, remotely using a 0.35-m f/7
reflector at Grove Creek Observatory, Trunkey, N.S.W., Australia,
Mar. 22.63-22.66) finds a coma of diameter about 15", elongated
toward p.a. 250 deg, on ten co-added 60-s exposures.

     2009 UT             R.A. (2000) Decl.       Mag.   Observer
     Mar. 20.65563   15 14 43.77   -36 41 46.5   15.9   McNaught

The available astrometry, the following very preliminary parabolic
orbital elements by B. G. Marsden, and an ephemeris appear on MPEC
2009-F60.

     T = 2008 Nov.  8.164 TT          Peri. = 299.227
                                      Node  = 219.027   2000.0
     q = 2.29052 AU                   Incl. =  85.783

                      (C) Copyright 2009 CBAT
2009 March 22                  (9033)            Daniel W. E. Green