From: LARRY KLAES (ljk4@msn.com)
Date: Mon Oct 07 2002 - 15:40:51 PDT
----- Original Message -----
From: Cary Oler
Sent: Monday, October 07, 2002 5:14 PM
To: sun-earth@SkyandTelescope.com
Subject: AstroAlert: More Northern Lights through 10 October
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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
07 October 2002
MIDDLE LATITUDE AURORAL ACTIVITY WATCH 07-10 OCTOBER
Some persistent and powerful auroral substorm activity has been
occurring over the last few days. The activity is in response to
interplanetary magnetic field, which has been oriented in a particular way
that promotes the occurrence of auroral substorm activity. What is unusual
about this activity is that it has been persistent now for several days. A
strong substorm over North America last night between 06:00 and 09:00 UTC
(2 am and 5 am EDT) resulted in some impressively bright auroral activity
over a good portion of the north-central United States. Experienced aurora
"hunters" in Northern Germany have also been able to consistently photograph
weaker levels of activity over the last 2 consecutive nights. This has been
possible due to the enlarged size of the auroral oval.
Similar sporadically strong activity is expected to continue over the
next 2 to perhaps 3 days. The possible arrival of one or two additional
coronal mass ejections may further help to improve the potential for substorm
activity over the next 48 hours.
Observers interested in looking for these apparations of "Northern
Lights" should be prepared to be PATIENT. The current activity is not
continually in-progress. Rather, it is occurring in sporadic and sometimes
infrequent bursts. Whether you spot anything may well depend on how long you
stay outside watching for activity.
For those with digital cameras (particularly those that are more light
sensitive), a well demonstrated technique for detecting activity from Germany
has been to perform a timed exposure (use a long exposure setting - 30
seconds or more if possible) of the northern sky (southern sky if you are in
the southern hemisphere). Since digital camera CCDs are often much more
sensitive to light than the human eyes are, they often show aurora that the
eyes can't see. Arcs and sometimes even rays or weak curtains may become
visible that aren't visible to the eye. If you have a camera, perform the
same type of timed exposure even if you can't see anything. You may be
surprised what comes back after the film has been developed.
A middle latitude auroral activity watch was issued earlier this UTC day
and will remain in-progress until 10 October. By then, solar wind conditions
might not be as favorable for producing enhanced levels of auroral activity.
Until then, keep your eyes on the skies. Some of the sporadic substorming
observed over the last 48 hours has been unusually powerful.
A copy of the watch statement has been included below for those who are
interested.
Images of the recent activity may be found at:
http://www.spacew.com/gallery. You can also submit your own images to the
gallery very easily by following the instructions available at:
http://www.spacew.com/gallery/help.html
Please report sightings of activity to the global auroral activity
observation network, so others may be informed of what you observe, and so
that a permanent record of ground-based activity may be maintained. The URL
for submissions is: http://www.spacew.com/submitsighting.html
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
MIDDLE LATITUDE AURORAL ACTIVITY WATCH
WATCH ISSUED: 05:50 UTC, 07 OCTOBER 2002
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
VALID BEGINNING AT: IMMEDIATELY
VALID UNTIL: 19:00 UTC (3 pm EDT) ON 10 OCTOBER
HIGH RISK PERIOD: 07 - 09 OCT (UTC DAYS)
MODERATE RISK PERIOD: 07 - 10 OCT
PREDICTED ACTIVITY INDICES: 22, 28, 25, 15 (07 OCTOBER - 10 OCTOBER)
POTENTIAL MAGNITUDE OF MIDDLE LATITUDE AURORAL ACTIVITY: MODERATE
POTENTIAL DURATION OF THIS ACTIVITY: MAIN BELT = VARIED AND SPORADIC
MINOR BELT = THROUGH 10 OCT
ESTIMATED OPTIMUM OBSERVING CONDITIONS: NEAR LOCAL MIDNIGHT
EXPECTED LUNAR INTERFERENCE: NIL
OVERALL OPPORTUNITY FOR OBSERVATIONS FROM MIDDLE LATITUDES: FAIR TO GOOD
AURORAL ACTIVITY *MAY* BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
OREGON TO SOUTHERN IDAHO TO WYOMING TO NEBRASKA TO IOWA TO NORTHERN
ILLINOIS TO NORTHERN INDIANA TO NORTHERN OHIO TO PENNSYLVANIA TO NEW
JERSEY.
ACTIVITY *MAY* ALSO BE OBSERVED APPROXIMATELY NORTH OF A LINE FROM...
UNITED KINGDOM TO NORTHERN BELGIUM TO NORTHERN NETHERLANDS TO NORTHERN
GERMANY TO NORTHERN POLAND TO LITHUANIA TO LATVIA TO NORTH-CENTRAL RUSSIA.
NEW ZEALAND AND PARTS OF SOUTHEASTERN AUSTRALIA MAY ALSO SPOT PERIODS OF
ACTIVITY.
SYNOPSIS...
A resumption of southwardly directed interplanetary magnetic fields has
been observed over the last 12 to 18 hours. An unconfirmed sighting of
auroral activity from Germany as well as a strong substorm interval over the
higher latitude North American region over the last hour has prompted the
issuance of this watch. Conditions may become sporadically favorable once
again for the production of auroral substorming. Some substorm activity has
the potential of being strong enough to produce some middle latitude
sightings. The new phase of the moon will contribute to the dark skies
necessary to spot periods of activity. However, observer patience may be
required as substorm intervals strong enough to observe from mid-latitudes is
not expected to be continual or frequent at this time.
Additional enhancements of activity may be observed on 08 and/or 09
October in response to two minor coronal mass ejections that are expected to
impact the Earth on these dates.
This watch will remain valid through 19:00 UTC (3 pm EDT) on 10 October.
It will then be updated or allowed to expire. For updated information, visit:
http://www.spacew.com/aurora/forum.html
PLEASE REPORT OBSERVATIONS OF AURORAL ACTIVITY TO:
http://www.spacew.com/submitsighting.html
WE WELCOME PHOTOGRAPHERS TO PLACE IMAGES IN OUR GALLERY
http://www.spacew.com/gallery
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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