Hi Anthony, here is the official IAU bulletin
Electronic Telegram No. 1882
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL
http://www.cfa.harvard.edu/iau/cbat.html
TRANSIENT FEATURES ON JUPITER
J. H. Rogers, Jupiter Section Director, British Astronomical Association,
reports on BAA Electronic Bulletin No. 00429 word of the discovery by
Anthony Wesley (Murrumbateman, NSW, Australia) of a "virtually black" spot in
Jupiter's South Polar Region, very similar in appearance to the impact spots
of comet D/1993 F2 in July 1994. Information at the web site
http://www.acquerra.com.au/astro/ notes that the discovery was made by
Wesley (0.37-m f/5 reflector) on July 19.56 UT and shows an image he obtained
(Point Grey Research Dragonfly2 mono camera, 60-s exposure) on July 19.66.
Rogers adds that the spot is at longitude 216 deg (System II) and that
T. Mishina (Japan) also reported the same spot in an image taken at about
the same time.
F. Marchis, University of California, Berkeley (UCB), and SETI Institute;
and M. H. Wong, Space Telescope Science Institute, report that analysis of
observations of Jupiter's atmosphere collected by P. Kalas, M. Fitzgerald and
J. Graham (UCB) using the NIRC2 near-infrared camera at the W. M. Keck II
telescope during July 20.468-20.474 UT (central meridian longitudes 283-288
deg, System III) revealed the presence of an anomalous bright feature
centered at planetographic coordinates 305 +/- 1.5 deg west, 57 +/- 1.5 deg
south. This feature is most likely linked to Wesley's dark spot,
interpreted to be an impact in the atmosphere of Jupiter. The scar, having
an area of about 200 million square km and well seen in the Kp filter centered
at 2.124 microns, has a complex shape, composed of an impact site with two
prominent features separated by about 2 degrees and an ejecta field that
extends some 10 deg toward the west. The scar is marginally detected in
observations recorded in H band (centered at 1.633 microns) and in CH4
(centered at 1.681 microns) filters. Further observations during July
20.619-20.627 (central meridian longitudes 54-62 deg) do not show evidence
for additional impacts. See also
http://cilaos.berkeley.edu/~fmarchis2/Jupiter2009/OurImages/Image_Keck.jpg
and
http://astro.berkeley.edu/~mikewong/G510/ircolor_annotation.pdf .
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2009 CBAT
2009 July 21 (CBET 1882) Brian G. Marsden