(meteorobs) NAMN Notes: September 2007

Sun Aug 26 19:52:15 EDT 2007

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NAMN Notes:  September 2007
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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.  A Change for NAMN...
2.  September - alpha Aurigids...
3.  Other September Meteor Activity...
4.  Upcoming Meetings...
5.  For more info...

1.  A Change for NAMN...

Well, meteor friends, it's time to say goodbye.  This Canadian writer is
stepping down from NAMN Notes and letting some evolution take over for
NAMN, our North American Meteor Network.

It's been 9 years.  Wow, it doesn't seem that long.  I started writing NAMN
Notes back in September of 1998.  Change is good for an organization though.
It brings in new ideas, new personalities - and a new perspective on
observing.

I will continue to write the occasional article from time to time, but the
monthly issues will be handled by our new writer.  I will also continue to
help out a bit on occasion "behind the scenes".

Mark Davis advised our NAMN staff this summer:

"I just wanted to bring you up to date on an upcoming change regarding our
monthly newsletter.  After 9 years, Cathy has decided to step down as the
newsletter writer.  It is hard to believe so many years have gone by, but it
proves how well (and smoothly) she performed her writing duties each month.
Cathy hopes to submit occasional articles for the newsletter, and will
continue other work with NAMN...  My heartfelt thanks go to Cathy for all
those dedicated years of putting out a great newsletter each month!!"

So, who is this new writer?  I will leave that as a surprise.  He will
introduce himself with the October issue.  He is an American with many years
of meteor observing experience - and a lot of technical knowledge about
meteors that will help our readers learn more about this science we all
love.  His style is quite different from mine, and will provide a refreshing
change for our readers!  He is enthusiastic, and witty - and cares deeply
about NAMN and what we are all trying to do.  You are in good hands...

2.  September - alpha Aurigids...

The alpha Aurigids (AUR) are the highlight of our September meteor
observing.  They started to become active about August 25th, and will peak
near 12h30m UT on September 1st according to the International Meteor
Organization (IMO) in their 2007 Meteor Shower Calendar.  UT refers to
Universal Time, at Greenwich, England.  For North American observers, this
means the hours before dawn on the 1st, with the far west coast highly
favored.

These are fast meteors, at about 66 km per second.  They can be seen through
until about September 8th.  ZHR rates at the peak are about 7 meteors per
hour - in a normal year.

What is ZHR?  This refers to Zenithal Hourly Rate, and is the number of
meteors that an observer would expect to see in an hour, on average, with
the unaided eye, if they are out observing under a dark sky and if the
radiant, the area in the sky where the meteors seem to come from, is
directly overhead.

Where is the radiant?  Check out the map on the IMO website at
http://www.imo.net/calendar/2007.

According to the International Meteor Organization:

" Of the... Aurigid sources, the alpha-Aurigids (AUR) are the more active,
with short unexpected bursts having given EZHRs of ~ 30-40 in 1935, 1986 and
1994, although they have not been monitored regularly until very recently,
so other outbursts may have been missed..."

The parent body of this shower is Comet Kiess, C/1911 N1.  Gary Kronk
writes, in his book "Comets - A Descriptive Catalog" about this comet
discovered July 7, 1911 at magnitude 6.0:

"Discovered by C.C. Kiess (Lick Observatory) on the edge of a photographic
plate he had taken with the Crocker Photographic Telescope...  On August
5, Raimond Moravansky (Moravia, Czechoslovakia) independently discovered
the comet at a magnitude near 5.5 and with a coma diameter of nearly 6
arcmin.  The comet was at its best on August 22, when it was described as
near magnitude 4...  A combination of the comet's low altitude, increasing
southern declination and decreasing brightness ended observations on
September 18, 1911.  The orbit is elliptical with a period near 2,500
years..."

The alpha Aurigids are a meteor shower that is gathering some news in the
press this year.  There is an interesting article in the September issue of
"Sky & Telescope" magazine written by Joe Rao.  It discusses the forecast
by Dr. Peter Jenniskens, based on calculations by Jenniskens, Vaubaillon and
Lyytinen.  Check out full details on Dr. Jenniskens' 2007 Aurigid website at
http://leonid.arc.nasa.gov/aurigids.html.  The meteor researchers discuss a
possible peak centered on 11.37 UT on September 1st with ZHR meteor rates
of possibly 200 per hour at the peak, and an abundance of bright meteors
(magnitude +3 to -2).  This shower is particularly interesting as its source
is debris from a long period comet.  Observations are encouraged!

If you want to help record visual data for the meteor researchers,
check out the NAMN Observing Guide for information on what to record.  Our
Guide can be found at http://www.namnmeteors.org/guide.html.  We record such
info as the time a meteor occurred, its magnitude (brightness), the shower
it belongs to, its speed, and other comments such as train left behind, or
color.  General information to record includes such things as how dark your
perceived sky is (limiting magnitude), and comments on weather and cloud
cover.  If you have any questions, drop a note to the NAMN Coordinator at
meteors at comcast.net

For visual observers, NAMN has a set of 4 star charts to help you judge the
brightness (magnitude) of the meteors you see.  They are also a great tool
for new observers to help you learn your constellations better.  The charts
can be printed off from http://www.namnmeteors.org/charts.html.  Set your
printer to landscape mode.

Forms to record your observations can be found at
http://www.namnmeteors.org/namn_form.html and
http://www.namnmeteors.org/appendixC.html

3.  Other September Meteor Activity...

We have several other meteor showers in September that are listed in the
International Meteor Organization's 2007 Meteor Shower Calendar.  According
to the IMO:

"The September Perseids and delta-Aurigids, whose activities and radiants
effectively overlap one another, were combined into one source in the
Working List up to 2006.  Since the activity curves show evidence for two
individual showers, we have split them into the September Perseids and
delta-Aurigids in the Working List for 2007.  Near September 17, activities
of both showers are actually interfering, but it is not recommended to
distinguish the showers as their individual radiants are not resolvable..."

The September Perseids (SPE) are active from September 5th to 17th, and peak
about September 9th.  These are fast meteors, at about 64 km per second.
The ZHR rate at the peak will be about 5 meteors per hour.  The radiant
position at the peak will be at 60 degrees, ie RA 4h0m, Dec +47.  A table
showing positions at 5 day intervals can be found at the end of the IMO 2007
Calendar at http://www.imo.net/calendar/2007

Starting about September 18th, the delta Aurigids (DAU) start to become
active and will run until about October 10th.  There may be a weak maximum
around September 24th.  The peak date is poorly defined and may occur as
late as October 4th.  ZHR rates at the peak will be about 2 meteors per
hour.  These are fast meteors, with a velocity of about 64 km per second.  A
map showing the radiant can be found at http://www.imo.net/calendar/2007

The Antihelion Source (ANT), the ecliptical activity, produces a ZHR of
about 3 meteors per hour with an average velocity of about 30 km per
second.  A map showing the movement of the radiant throughout the month can
be found at http://www.imo.net/calendar/2007

For other September minor showers not on the International Meteor
Organization's "Working List of Visual Meteor Showers," and for a wealth of
historical information on all showers, check out Gary Kronk's 'Meteor
Showers Online' website at http://meteorshowersonline.com

Besides September's main activity and other minor showers, there is also
sporadic meteor activity.  This sporadic meteor activity is about 7 meteors
per hour visible to the unaided eye.  Some of these are random and some
belong to old untraceable meteor showers.

For those of you interested in plotting your meteors (recommended for
serious observations), special IMO plotting maps can be ordered through
Robert Lunsford of the International Meteor Organization. For details,
contact him directly at lunro.imo.usa at cox.net

The magnitudes of the planets just before mid-month are as follows:
Venus     -4.4   in morning twilight
Jupiter   -2.1   in early evening sky
Mars       0.2   in Taurus
Saturn     0.7   in Leo in morning twilight

For a sky chart showing the positions of these planets in September,
go to http://www.heavens-above.com, 'Select' your country, type in the name
of your nearest city, and then go to 'Whole Sky Chart'.  Pick 'black on
white' before printing.  The Heavens Above website will also tell you when
to look to see the International Space Station go over your observing site.

The phases of the moon for September are as follows:
Tues. Sept.  4   last quarter
Tues. Sept. 11   new moon
Wed.  Sept. 19   first quarter
Wed.  Sept. 26   full moon

For phases of the moon, a great monthly moon calendar can be printed off
from http://stardate.org/nightsky/moon.  For the NASA kids' calendar,
go to http://spaceplace.nasa.gov/en/kids/calendar.shtml

For up to date info on what's happening in the sky right now, check out
'SpaceWeather' at http://www.spaceweather.com

4.  Upcoming Meetings...

September 6-9, 2007, Ivy, Ontario, Canada...

HSP 2007, the Huronia Star Party, a small but growing amateur astronomical
gathering, will be held about an hour's drive north of Toronto, Ontario, at
Camp Saulaine.  Dr. Peter Brown of the University of Western Ontario Meteor
Physics Group will give several talks - "Impacts of Large Bolides as
Observed by Earth Orbiting Satellite and Infrasound Networks" and "The Fall
and Recovery of the Tagish Lake Meteorite."  Details on the other speakers,
and on this casual but informative astronomical gathering can be found at
http://www.cois.on.ca/~ssaa

For information on other astronomy meetings, see: 'International
Astronomy Meetings List' at http://cadcwww.hia.nrc.ca/meetings

If you know of other astronomical meetings where talks on meteors will be
given, please drop a note to our NAMN Coordinator and let us know!

5.  For more info...

NAMN email: namn at namnmeteors.org
NAMN website: http://www.namnmeteors.org

Mark Davis, meteors at comcast.net
Goose Creek, South Carolina, USA
Coordinator, North American Meteor Network

Cathy Hall, chall at cyberus.ca
Ottawa, Ontario, Canada
Writer, NAMN Notes

Lew Gramer, dedalus at alum.mit.edu
Homestead, Florida, USA
Coordinator, Public Outreach
Owner/Moderator, 'MeteorObs'

Kevin Kilkenny, namnfireball at earthlink.net
Staten Island, New York, USA
Coordinator, Fireballs and Meteorites

Back issues of NAMN Notes can be found online 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:
Contact Lew Gramer at: dedalus at alum.mit.edu

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Here's to 'Clear Skies' for September...

September 2007 NAMN Notes
written by Cathy Hall & edited by Mark Davis
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