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NAMN Notes: September 2002
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Introduction:
NAMN Notes is a monthly newsletter produced by the North American
Meteor Network, and is available both via email, and on the NAMN
website at: http://www.namnmeteors.org
Contents:
1. Alpha Aurigids... September's Main Shower...
2. Other Activity This Month...
3. August Fireballs...
4. Web People - Time to Update Before Leonids...
5. Upcoming Meetings...
6. For more info...
1. Alpha Aurigids... September's Main Shower...
After all the many showers to keep track of in August, September is a
quiet month in comparison. However, this is not necessarily a bad thing!
With the promise of a very active November with a Leonid storm coming up,
meteorobservers can us for that special event...
The alpha Aurigids (AUR) reach a maximum on the 1st, so the first
weekend of September is the prime observing time for this shower!
The radiant will be at 084 degrees, ie. RA 5h 36m, Dec +42, which is
about 5 degrees to the left of the star eta Auriga, a star with the
rather cool name of Hoedus II. These are fast meteors, with a velocity
of about 66 km per second. They can be seen only until about September 5th.
The alpha Aurigids are believed to be associated with Comet Kiess
1911 II. This comet was discovered by C.C. Kiess of the Lick Observatory
on a photographic plate taken with the Crocker Photographic Telescope. It
has an elliptical orbit with a period of about 2500 years.
The Zenithal Hourly Rate (ZHR) at maximum will be about 10 meteors per
hour. This is the average number of meteors that an observer would
expect to see with the unaided eye, if they are out under a dark country
sky, and if the radiant, the area in the sky where the meteors seem to come
from, is directly overhead. According to the IMO, the International Meteor
Organization, in their 2002 Meteor Shower Calendar, the alpha
Aurigids "peak on September 1, 6h UT", so that would be the time to expect
the highest rates.
The activity level has been known to vary from year to year, and can
occasionally be 3 to 5 times higher. So - get out and take a look at
this shower, and let us hear about your observations!
2. Other Activity This Month...
September has little main shower activity besides the alpha Aurigids,
if you look at the 2002 IMO Meteor Shower Calendar at
http://www.imo.net/calendar/cal02.html.
The delta Aurigids (DAU) reach a maximum on September 8th, with a
radiant at 060 degrees, ie. RA 4h 00m, Dec +47, which is about 3 degrees
to the left of the star delta Perseus. These are fast meteors, with a
velocity of about 64 km per second.At maximum, ZHR rates will be about
6 meteors perhour. The shower lasts until about October 10th, but with
lesser rates.
The Pi scids (SPI) last for the whole month of September, but reach a
maximum on September 20th. The radiant on that date will be at 005
degrees, ie. RA 0h 19.8m, Dec -01, which is about 15 degrees south of
gamma Pegasus, the bottom left star of the Great Square of Pegasus.
These are slow meteors, with a velocity of about 26 km per second.
ZHR rates on the 20th will be about 3 meteors per hour, and rates the
rest of the month much less.
For information on minor showers visible in September - and there is
always minor activity - check out Gary Kronk's "Comets and Meteor
Showers" website at http://comets.amsmeteors.org.
One minor shower of note in September is the Aries-Triangulid activity
around September 12th, first detected by Gary Kronk of Illinois,
George Gliba of Maryland, and Kurt Sleeter of Illinois. Observers are
encouragedto watch for any possible activity this year. The radiant
would be at approximately RA 2h 00m, Dec +29, which is very near the
star alpha Triangulum. For more details, check out Kronk's website at
http://comets.amsmeteors.org/meteors/showers/aries_triangulids.html.
Another item of note is the daytime meteor shower called the
Sextantids. These are described in length on Kronk's site at:
http://comets.amsmeteors.org/meteors/showers/sextantids.html
This shower was discovered by A.A. Weiss in 1957 during radio studies
in South Australia. It is interesting that the International
Meteor Organization (IMO) comments on this shower this year in their
notes to visual observers:
"For daylight radio observers... there remain(s)... a tricky
visual shower, the Sextantids (maximum expected on September 27,
15h UT, but possibly occurring a day earlier. In 1999 a strong
return was detected at lambda about 186 degrees, equivalent to 2002
September 29). The waning Moon presents extra problems for visual
observers hoping to catch some Sextantids in late September, though
the radiant rises less than an hour before dawn in
either hemisphere."
The average radiant position detected (by radio means) in 1961 was
151.7 degrees, ie. RA 10h 6.6m, Dec -0.1, which is very near the star
alpha Sextans, and about 12 degrees due south of the star Regulus in
Leo.
Besides recognized main showers, and other minor showers, there is
also sporadic meteor activity in September. This sporadic activity is
about 7 meteors per hour, visible to the unaided eye. This activity is
comprised partly of random meteors and partly of meteors that belong to
long-ago, now untraceable showers.
This month, the phases of the moon are as follows:
Sat. Sept. 7 - new moon
Fri. Sept. 13 - first quarter
Sat. Sept. 21 - full moon, the 'Harvest Moon'
Sun. Sept. 29 - last quarter
Planets this month are few in the evening sky. Venus sets very
early, at about magnitude -4.5. In the morning sky we have Saturn
and Jupiter. Saturn moves into Orion on September 1st, and gets quite
high in the sky this month at about magnitude 0. Jupiter is in Cancer,
and by the end of the month, will be about 20 degrees above the eastern
horizon at the beginning of morning twilight, at about magnitude -1.9.
For information on what to record when meteor observing, check out
our NAMN Observing Guide at
http://www.namnmeteors.org/guide.html
For recording sheets for your meteors, go to
http://www.namnmeteors.org/reports.html
For some great star charts with standard stars marked, to use in
estimating the brightness of the meteors you see, go to
http://www.namnmeteors.org/charts.html
And - if you have any questions on observing, drop a note to our
NAMN Coordinator at meteors@comcast.net.
3. August Fireballs...
A summary of August fireball reports submitted to NAMN is as follows,
from Kevin Kilkenny, our Coordinator, Fireballs and Meteorites:
Date Location Direction Mag. Fragmentation?
From-To
8/2 Midland, Ont. SE-S -10 yes
8/3 Effingham, Ill. E-W -3 no
8/9 Hayden Lake, ID N-W -8 no
8/11 Niagara Falls, Ont. N-NW -5 no
8/12 Fenton, MO N-NNW -6 yes
8/12 UK N-S -8 no
8/14 Las Vegas, NV S-N -5 yes
8/18 West Bend, WI SE-NE -11 yes
Anyone wishing to contribute to the international fireball database
may do so at:
http://www.namnmeteors.org/fireball/namnreport.html
or at
http://www.namnmeteors.org/fireball/report.html
for beginners or novices.
Questions on fireballs should be directed to Kevin Kilkenny at
Mail4Meteors@aol.com
4. Web People - Time to Update Before Leonids!...
This Canadian co-author has been doing some web cruising in
preparation for an upcoming article on the Leonid meteor shower
in November... and finding all kinds of deadbeat links out there in
cyberspace! So... while your kids are getting ready to go back to
school this fall, here is some homework for all of you as well!
If you have an astronomy webpage of any kind - your own personal
page, or for your group - go through it and check each and every
cross-reference and link. I have been finding all kinds of badly
outdated links on pages. These are not just in the "Links" sections
of webpages, but throughout the webpages themselves. I will be sending
friendly emails to those I find in hopes of getting them updated quickly.
With Leonids coming up in November - and web traffic due to
exponentially increase - broken links can mean problems for all observers
trying to get information on this big event. Pleasetake this time now,
in September, to go through and make sure all the links and cross-references
throughout your website actually do work!
Some of the common addresses that have changed in the past couple
years and should be corrected on your websites include the following.
I'm sure there are many more links to correct, but these are just some
of the ones I came across on websites multiple times:
Dr. Peter Jenniskens' Leonid MAC site, correct address is now:
http://leonid.arc.nasa.gov
Sky and Telescope, correct address is now:
http://skyandtelescope.com
NAMN, North American Meteor Network, correct address is now:
http://www.namnmeteors.org
our NAMN Guide "Meteor Showers and their Observation",
correct address is now:
http://www.namnmeteors.org/guide.html
Gary Kronk's Comets and Meteor Showers, correct address is now:
http://comets.amsmeteors.org.
For those of you interested in doing a bit of advance reading on
Leonids,
check out the following:
2002 Predictions by Robert McNaught and David Asher:
http://www.arm.ac.uk/leonid/encounters.html
2002 Predictions by Dr. Peter Jenniskens:
http://leonid.arc.nasa.gov/1998.html
(and yes, although it is labeled weird, this is the correct address!)
2002 Predictions by Esko Lyytinen, Markku Nissinen and Tom Van
Flandern:
http://www.ursa.fi/ursa/jaostot/meteorit/leoeng02.html
More information on the Leonids will be coming up in the next issues
of NAMN Notes... and we hope that by then, all of your websites will
be up to date as well!
5. Upcoming Meetings...
September 3-6, Washington, DC, USA...
The Workshop on Scientific Requirements for Mitigation of Hazardous
Comets and Asteroids, sponsored by NASA, will be held in Washington, DC.
The workshop will review current knowledge of the physics and chemistry
of the interiors of small cometary nuclei and asteroids, and will work
towards several goals: determination of requirements for collision
avoidance and impact mitigation technologies, determination of mission
models and instrumentation needed, and construction of a roadmap for
achieving the knowledge on which to base future systems to deal with
possible impacts. A list of the confirmed invited speakers can be found
at http://www.noao.edu/meetings/mitigation/invited.html.
For information, contact Nalin Samarasinha at nalin@noao.edu
and check out the conference
website at http://www.noao.edu/meetings/mitigation.
September 26-29, 2002, Frombork, Poland...
IMC 2002, the International Meteor Conference, will be held in
Frombork, Poland. This is the annual conference of the International
Meteor Organization and welcomes all meteor observers, both amateur
and professional. For information, check out http://www.imo.net and
http://www.astrouw.edu.pl/~olech/pkim/imc2002/imc.html.
For specific questions, contact Mariusz Wisniewski at
pkim@astrouw.edu.pl
For more information on upcoming astronomy meetings, see:
"International Astronomy Meetings List"
http://cadcwww.hia.nrc.ca/meetings
6. For more info...
NAMN email: namn@atmob.org
NAMN website: http://www.namnmeteors.org
Mark Davis, meteors@comcast.net
Goose Creek, South Carolina, USA
Coordinator, North American Meteor Network
Cathy Hall, chall@cyberus.ca
Metcalfe, Ontario, Canada
Co-author, NAMN Notes
Lew Gramer, dedalus@alum.mit.edu
Medford, Massachusetts, USA
Coordinator, Public Outreach
Owner/Moderator, 'MeteorObs'
Kevin Kilkenny, Mail4Meteors@aol.com
Staten Island, New York, USA
Coordinator, Fireballs and Meteorites
Back issues of NAMN Notes can be found on-line at the NAMN website
and in the MeteorObs archives at:
http://www.meteorobs.org by selecting 'Browse
Archive by Month'
To subscribe to the meteor email list or to find out information on
our weekly chat sessions:
Contact Lew Gramer at: dedalus@alum.mit.edu
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Here's to 'Clear Skies' for September...
September 2002 NAMN Notes co-written
by Mark Davis and Cathy Hall
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