From: LARRY KLAES (ljk4@msn.com)
Date: Thu Nov 21 2002 - 05:12:03 PST
----- Original Message -----
From: Cary Oler
Sent: Wednesday, November 20, 2002 4:42 PM
To: sun-earth@SkyandTelescope.com
Subject: AstroAlert: TWO Sunspots Visible to the Unaided Eye and an Aurora Watch!
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This Is SKY & TELESCOPE's AstroAlert for Sun-Earth Interactions
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A s t r o A l e r t
Sun-Earth Alert
Solar Terrestrial Dispatch
http://www.spacew.com
20 November 2002
Contents
TWO LARGE SUNSPOTS VISIBLE TO THE UNAIDED EYE
MIDDLE LATITUDE AURORAL ACTIVITY WATCH
TWO LARGE SUNSPOTS VISIBLE TO THE UNAIDED EYE
John C. McConnell has confirmed that there are currently TWO large
sunspots visible to the unaided protected eye. "Unaided protected eye" means
he observed these sunspots using a suitable solar filter but without the aid
of binoculars or a telescope. ALWAYS use an acceptable solar filter when
viewing the Sun, or use a safe solar image projection technique.
The sunspots visible to the unaided eye are identified as Regions 197
and 198. Region 197 is the northern-most spot - a single large symmetrical
umbra surrounded by a nearly symmetric penumbra. Region 198 is a bit more
complex and consists of multiple umbra surrounded by a slightly asymmetrical
penumbra. Region 198 has produced some minor M-class x-ray flares
over the last 24 hours. These small, but moderately energetic solar
explosions could involve coronal mass ejections capable of affecting
geomagnetic and auroral activity at the Earth. There is one event in
particular today that is being investigated as a possible Earth-ward directed
coronal mass ejection.
Also of potential interest to solar observers having telescopic solar
prominence filters or hydrogen-alpha filters installed is the large
quiescent prominence that is visible off the eastern solar limb.
MIDDLE LATITUDE AURORAL ACTIVITY WATCH
Effects of a coronal mass ejection that was observed impacting the Earth
near 11:10 UTC (6:10 am EST) on 20 November are currently being observed.
Periods of minor geomagnetic storming has been observed following a strong
southward turning of the interplanetary magnetic field (IMF) which results in
more favorable conditions that can lead to auroral substorm formation. High
latitudes have observed auroral storm conditions over the last several hours.
Although no significant storm activity is expected, some dark-sky
upper-middle latitude regions may spot periods of enhanced auroral activity.
The official watch statement has been appended below. For current
real-time conditions and plots, visit: http://www.spacew.com/plots.html.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
MIDDLE LATITUDE AURORAL ACTIVITY WATCH
WATCH ISSUED: 19:20 UTC, 20 NOVEMBER 2002
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VALID BEGINNING AT: EFFECTIVE IMMEDIATELY
VALID UNTIL: 19:00 UTC (2 pm EST) ON 21 NOVEMBER
HIGH RISK PERIOD: 20 - 21 NOV (UTC DAYS)
MODERATE RISK PERIOD: 20 - 21 NOV
PREDICTED ACTIVITY INDICES: 25, 20, 20, 15 (20 NOVEMBER - 23 NOVEMBER)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE
POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = 6 - 12 HOURS (SEE WARNING)
MINOR BELT = 12 - 24 HOURS
ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR LOCAL MIDNIGHT
EXPECTED LUNAR INTERFERENCE: HIGH
OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO POOR
AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
NORTHERN OREGON TO IDAHO TO NORTHERN WYOMING TO SOUTH DAKOTA TO SOUTHERN
MINNESOTA TO WISCONSIN TO MICHIGAN TO DARK SKY SITES OF NEW YORK STATE TO
NEW HAMPSHIRE.
ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
NORTHERN TO CENTRAL UNITED KINGDOM TO THE NORTHERN NETHERLANDS TO NORTHERN
GERMANY TO NORTHERN POLAND TO LITHUANIA TO LATVIA TO NORTHERN RUSSIA.
SOUTHERN REGIONS OF NEW ZEALAND AND EXTREME SOUTHEASTERN AUSTRALIA MAY
ALSO SPOT PERIODS OF ACTIVITY.
SYNOPSIS...
A coronal mass ejection impacted the ACE spacecraft near 10:21 UTC on 20
November. This disturbance has produced a strong southward rotation of the
interplanetary magnetic field and is resulting in periods of minor to major
geomagnetic and auroral substorm conditions over the high and upper middle
latitude regions. European regions may be able to spot periods of activity
over the next several hours while these favorable conditions exist. North
American observers will be at the mercy of the IMF, which may (or may not)
remain southward long enough to keep substorming active until darkness falls.
In any event, strong interference from the brightness of the moon will
inhibit middle latitude observations of auroral storm activity. Nevertheless,
middle latitude observations of activity will be possible over the next 6 to
12 hours (with a chance of minor lingering activity thereafter).
This watch will remain valid through 19:00 UTC (2 pm EST) on
21 November. It will then be updated or allowed to expire. For updated
information, visit: http://www.spacew.com/aurora/forum.html. For real-time
plots of current activity, visit: http://www.spacew.com/plots.html
PLEASE REPORT OBSERVATIONS OF AURORAL ACTIVITY TO:
http://www.spacew.com/submitsighting.html
Observations reported here are permanently recorded for future study and
are immediately made available in real-time to a large network of observers
world-wide via the Internet, e-mail and pager. If you observe activity, your
assistance to contribute to this database would be appreciated.
** End of the AstroAlert Bulletin **
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