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
1. A Change for NAMN...
2. September - alpha Aurigids...
3. Other September Meteor Activity...
4. Upcoming Meetings...
5. For more info...
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...
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 our 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@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
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@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 July, 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 ISS, 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 for July, 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
September 6-9, 2007, Ivy, Ontario, Canada...
HSP 2007, the Huronia Star Party, a small but growing 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 upcoming 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 the NAMN Coordinator and let us know!
NAMN email: namn@namnmeteors.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
Ottawa, Ontario, Canada
Writer, NAMN Notes
Lew Gramer, dedalus@alum.mit.edu
Homestead, Florida, USA
Coordinator, Public Outreach
Owner/Moderator, 'MeteorObs'
Kevin Kilkenny,
namnfireball@earthlink.net
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