[IAUC] IAUC 8830: C/2007 H1; C/2007 E2; 2P [25139-2007/05-R1]

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                                                  Circular No. 8830
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS en CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT en CFA.HARVARD.EDU (science)
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Phone 617-495-7440/7244/7444 (for emergency use only)


COMET C/2007 H1 (McNAUGHT)
     R. H. McNaught reports his discovery of a new comet on CCD
images taken with the 0.5-m Uppsala Schmidt telescope in the course
of the Siding Spring Survey (discovery observation tabulated below),
the object then reported as having a 12" coma and a 25" tail in p.a.
250 deg.  Following posting on the Minor Planet Center's 'NEOCP'
webpage, several CCD astrometric observers have commented on the
cometary appearance of this object.  G. Hug (Scranton, KS, 0.30-m
Schmidt-Cassegrain reflector) reports that his images from Apr.
18.44 UT show the comet to be slightly diffuse.  E. Guido and G.
Sostero, remotely using a 0.25-m f/3.4 reflector at Mayhill, NM,
write that the co-adding of twenty 60-s unfiltered exposures, taken
on Apr. 18.46-18.47, reveals the presence of a coma nearly 20" in
diameter and a broad tail nearly 1' long toward p.a. 250 deg;
co-adding ten 60-s unfiltered exposures taken on Apr. 19.47 shows a
coma that is nearly 17" in diameter (total mag about 16.3) and a
tail almost 45" long toward p.a. 255 deg.  N. Teamo and S. Hoenig
report that images obtained with a 0.41-m f/8 reflector at Punaauia,
Tahiti, on Apr. 19.6 show a 14" coma and a 2'.2 tail in p.a. 252
deg.

     2007 UT             R.A. (2000) Decl.       Mag.
     Apr. 17.78663   21 59 34.74   - 9 09 15.9   16.1

The available astrometry, the following preliminary parabolic
orbital elements, and an ephemeris appear on MPEC 2007-H32.

     T = 2007 June 15.828 TT          Peri. = 181.324
                                      Node  = 147.663   2000.0
     q = 2.61460 AU                   Incl. =  11.002


COMET C/2007 E2 (LOVEJOY)
     Further visual total-magnitude estimates (cf. IAUC 8820): Mar.
24.66 UT, 8.7 (J. Drummond, Gisborne, New Zealand, 8-cm refractor):
Apr. 12.17, 7.7 (J. J. Gonzalez, Asturias, Spain, 25x100 binoculars);
16.67, 7.9 (S. Rae, Hamilton, New Zealand, 10x50 binoculars); 18.68,
8.0 (Rae).


COMET 2P/ENCKE
     Visual total-magnitude estimates with 25x100 binoculars: Apr.
13.85 UT, 7.7 (J. J. Gonzalez, Asturias, Spain); 14.50, 7.4 (M.
Lehky, Bacetin, Czech Republic); 17.85, 6.7 (Gonzalez).

                      (C) Copyright 2007 CBAT
2007 April 20                  (8830)            Daniel W. E. Green