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NAMN Notes: August 2005
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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. Perseids - Highlight of the Summer!...
2. Meteors from Aquarius...
3. Other August Showers...
4. Upcoming Meetings...
5. For more info...

The Perseids (PER) are the highlight of our summer meteor season! This year they peak on August 12th between 17h and 19h30m UT, Universal Time, for the 'traditional peak', with an estimated ZHR rate of about 100 meteors per hour.

What is ZHR? This is Zenithal Hourly Rate, and is the number of meteors, on the average, that an observer would expect to see in an hour if the radiant, the area in the sky where the meteors seem to come from, is directly overhead - and if an observer is out under dark country skies. If the radiant is not overhead, you will see less. If your sky is not really dark, you will see less. So - to see as many meteors as possible, get away from city lights and try to observe when the shower radiant is higher in the sky.

Perseids are fast meteors with a velocity of about 59 km per second. They can be seen until about August 24th. Where is the radiant, ie. where do they seem to come from? Check out the map on the website of the IMO, the International Meteor Organization, at http://www.imo.net/calendar/cal05.html#perseids

According to the IMO, we could possibly see a primary peak time around 18h30m UT on August 12 - and we could see a possible secondary peak about 3h UT on August 13th. Different years have yielded different observational results - so it is very useful to gather data to help out the meteor researchers!

If you want to record data on these showers 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 our NAMN Coordinator at meteors@comcast.net

Forms to record your observations can be found at

http://www.namnmeteors.org/namn_form.html and
http://www.namnmeteors.org/appendixC.html

These meteors are generally bright with an average magnitude of about 2.3, according to Gary Kronk on his authoritative website 'Comets and Meteor Showers'. This is roughly the brightness of the stars in the Big Dipper. A large percentage of Perseids have persistent trains - as many as 45% of all Perseids by some accounts. Their brightness and their trains left behind make them beautiful meteors to witness. The average brightness of the meteors can also be seen to change from night to night, as the comet debris that causes the meteors has been sorted by particle size over time. Kronk's website can be found at http://comets.amsmeteors.org

The Perseids are one of the oldest meteor showers that mankind has records for. The earliest reference to the shower seems to have been in the year 36 AD in China. Because the path of the Perseids is highly inclined to the ecliptic, it has not been affected as much over the millennia by the disturbing influences of our major planets that travel basically along the ecliptic path. As a result, the Perseids are a reliable meteor shower, seen in strength each year.

The Perseids were also the first meteor shower to be proven to be associated with a comet. This was found by Giovanni Virginio Schiaparelli (1835-1910), more often remembered for giving the name canals or channels to the markings on the planet Mars. The parent body of the Perseid shower is called Comet 109P/Swift-Tuttle after its discovery in 1862 by several Americans - Lewis Swift of Marathon, New York and Horace Tuttle of Harvard Observatory, Massachusetts. In late August and early September of that year, the comet reached a magnitude of about 2, about as bright as the stars in the Big Dipper, and it had a tail length of between 25 and 30 degrees, about 5-6 times the distance between the pointer stars of the Big Dipper.

When you watch the Perseid meteors this year - and look at Mars in your morning sky as well - think of Schiaparelli, Swift and Tuttle - and their part in this wonderful meteor shower!

The August sky is full of meteors from Aquarius - in addition to all the Perseids.

The southern delta Aquarids (SDA) reached a peak on July 28th, but can be seen until about August 19th. These are average velocity meteors at about 41 km per second. ZHR rates in July were about 20 meteors per hour, but August rates will be much lower.

The southern iota Aquarids (SIA) reach a maximum on August 4th and run through until about August 15th. These are slower than the delta's with a velocity of about 34 km per second, but still classed as average velocity. At the peak on August 4th, the ZHR rate will be about 2 meteors per hour.

The northern delta Aquarids (NDA) peak on August 8th and last until about August 25th. These are average velocity at about 42 km per second, very similar to the southern delta's. At their peak on August 8th, they will reach a ZHR of about 4 meteors per hour.

The northern iota Aquarids (NIA) peak on August 19th and run until the end of the month. These are average velocity as well, at about 31 km per second, very similar to the southern iota's. On the 19th, ZHR rates will be about 3 meteors per hour.

All these showers have low rates - so will an observer notice them? The answer is yes! Add them all together, and they total a quite decent hourly activity. The International Meteor Organization has maps showing all these various Aquarid radiants on their website at http://www.imo.net/calendar/cal05.html#aquarid-capricornid. If you look at the Aquarid radiants on any given night, they form sort of a parallelogram in the sky which helps in keeping track of them.

NAMN has some good star charts to mark all these radiants on before you go out observing. These charts also show constellations for the whole sky and give the brightness of a number of stars to use in judging the magnitude of the meteors you see. Our 4 printable charts can be found at http://www.namnmeteors.org/charts.html. Set your printer to 'landscape' mode.

For those observers interested in trying something a bit different, the Aquarids are "rich in faint meteors, making them well-suited to telescopic work" according to the IMO. For those interested in trying meteor work by telescope instead of just with the unaided eye, check out the telescopic meteors section of the IMO at http://www.imo.net/tele/index.html

The Pisces Austrinids (PAU) peaked back on July 28th, but can be observed until about August 10th. These are average velocity meteors at about 35 km per second. ZHR rates were about 5 meteors per hour at the peak, but will be lower in August. For a map showing the radiant, go to http://www.imo.net/calendar/cal05.html#piscis-austrinids

Lastly, the alpha Aurigids (AUR) start to become active about August 25th, although will not peak until September 1st. These are fast meteors at 66 km per second. ZHR rates on September 1st will reach about 7 meteors per hour, but rates in August will be lower. Where is the radiant? Check out http://www.imo.net/calendar/cal05.html#alpha-aurigids Monitoring this shower may yield some surprises - it had short unexpected bursts of about 30-40 meteors per hour in 1935, 1986 and 1994 - and some years may have been missed due to a shortage of observers. Check out this shower and send in your observations!

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

Planets at midmonth, and their magnitudes, for northern observers, are:

Venus        -3.8  very low in west-northwest in evening twilight
Jupiter      -1.8  in Virgo, low in west-southwest in evening sky
Mars         -0.6  in Aries
Saturn        0.2  in Cancer, low in east-northeast in morning sky

For a sky chart showing the positions of all the planets visible this month, go to http://www.heavens-above.com, select your country, then your city, and go to 'Whole Sky Chart'.

The phases of the moon for August are as follows:

Fri. Aug.  5  new moon
Sat. Aug. 13  first quarter
Fri. Aug. 19  full moon
Fri. Aug. 26  last quarter

For a great printout of moon phases for the month, check out http://stardate.org/nightsky/moon

August 7-12, 2005, Brazil...
ACM 2005, the IAU Symposium 229: Asteroids, Comets, Meteors, will be held in Rio de Janeiro, Brazil. The main topics of the conference will be space missions, internal structure of asteroids and comets, connections between asteroids, cometary nuclei and Trans-Neptunian Objects (TNO's), connections between asteroids and meteorites, connections between comets, meteor showers and interplanetary dust, minor body dynamics, collisions and impacts, Near-Earth Objects (NEO's), origin and evolution of our Solar System and extra-solar planetary systems. The website for the conference is at http://www.on.br/acm2005. For more information, contact Daniela Lazzaro or Fernando Roig at acm2005@on.br

September 10-14, 2005, Belgium...
'Radio Meteor School 2005' will be held in Oostmalle, Belgium. This will be a five day tutorial on the physical and mathematical theory of radio meteor observations, given by Dr. Oleg Belkovich of Russia. This workshop is for serious radio meteor observers. The cost for the workshop is about 150 Euros. For more information, check out the IMO website at http://www.imo.net/imc2005/radioschool.php and contact the organizers at imc2005@imo.net

September 15-18, 2005, Belgium...
The 2005 IMC, International Meteor Conference of the IMO, the International Meteor Organization, will be held in Oostmalle, Belgium. Oostmalle is about 70 km north of Brussels, and about 30 km northeast of Antwerp. The conference is being organized by Urania, the public observatory of Antwerp. Accommodation will be at the Provinciaal Vormingscentrum Malle, with an excursion to the city of Lier. This is a great opportunity to meet and chat with meteor observers from all around the globe - so mark it on your calendar now, and plan to attend! The participation fee for those now registering is 130 EUR, and includes all accommodation, all meals, and the conference registration. Financial assistance is available in some cases. There will be a guest lecture by Prof. Dr. Philippe Claeys on meteorite impacts. For information on the conference, check out http://www.imo.net/imc2005. For questions, contact Jan Verbert at imc2005@imo.net

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

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