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. Eta Aquarids - Comet Halley and the Meteors...
2. Watching the Birth of a New Meteor Shower - by G.W. Gliba...
3. Other May Meteor Activity...
4. Upcoming Meetings...
5. For more info...
May brings the eta Aquarids - one of the meteor showers associated with Halley's Comet. This is one of the best meteor showers of the year, and although close to full moon, will still reward those who head out to the countryside to relax and enjoy them.
It is wonderful to think as we observe these meteors that we are seeing pieces of debris from the famous Halley's Comet. But wait - did Halley really discover this comet? Surprisingly, no. Halley became famous for realizing that the comets of 1531, 1607 and 1682 were all one and the same comet. He found this out by comparing the information about their orbits. It was this significant discovery that resulted in these comets being renamed...Comet Halley.
Halley contributed a great deal to science - and in many ways that most people are not aware of. In the field of astronomy, he compiled the first systematic catalogue of stars in the southern hemisphere. He was the first to recognize that stars move in relation to one another. He noted that observing transits of Venus passing in front of the sun would make it possible to calculate the distance from the sun to the earth. He became Astronomer Royal in Great Britain in 1720, and held the post for 21 years until shortly before his death at Greenwich in his late 80's.
In fields other than astronomy, Halley was also well known. He designed an underwater diving bell. He published the very first meteorological map showing prevailing winds over the oceans. He produced one of the earliest studies of human mortality, which was quite influential in the actuarial industry. He was a naval captain of a ship called the Paramore Pink, and sailed all over the Atlantic Ocean charting the variation of the earth's magnetic field. He persuaded Newton to publish the Principia Mathematica, and paid for the publishing costs out of his own pocket.
The eta Aquarid (ETA) meteor shower reaches a maximum on May 6th this year, at about 12h UT, according to the International Meteor Organization (IMO). For observers in eastern North America on EDT, this means 4 hours earlier than UT, Universal Time, at Greenwich, England - in other words, about 8 a.m. on the 6th. This means that the hours between about 2.30 a.m. and dawn on the 6th should be the best viewing for eastern North America. The shower runs from about April 19th until May 28th. Don't forget that the meteors come from the constellation of Aquarius - and Aquarius doesn't start to rise until the morning hours.
These are fast meteors with a velocity of about 66 km per second. ZHR rates at the peak will be about 60 meteors per hour, with lesser rates the further you are from the peak date.
What is ZHR? ZHR refers to Zenithal Hourly Rate, and is the number of meteors that an observer would expect to see, on average, 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. The very bright moon will hamper rates this year however, and will wash out many fainter meteors.
The radiant at maximum is at 338 degrees, ie RA 22h 31.8m, Dec -01, which is very near the star eta Aquarius on a star atlas. The radiant does move over time though - check out the map on the website of the IMO at http://www.imo.net/calendar/2005/spring
According to the IMO, in their Meteor Shower Calendar:
"A fine, rich stream associated with Comet 1P/Halley, like the Orionids of October, but one visible for only a few hours before dawn... The fast and often bright meteors make the wait for radiant-rise worthwhile, and many events leave glowing persistent trains after them. While the radiant is still low, eta-Aquarids tend to have very long paths... " "A relatively broad maximum, sometimes with a variable number of submaxima, usually occurs in early May... IMO analyses in recent years... have shown that ZHRs are generally above 30 between about May 3-10, and that the peak rates appear to be variable on a roughly 12-year timescale. The next highest rates should fall towards 2008-2010, if this Jupiter-influenced cycle is borne-out... "
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
There is a newly confirmed annual meteor shower called the Eta Lyrids (ELY) that is associated with a bright comet that was seen near Earth just 24 years ago, in the spring of 1983. Little did we know at the time that we would actually be seeing the birth of a new annual meteor shower. This is a very rare event to witness in one's lifetime. Meteor showers are sometimes discovered, but seldom seen being born.
That comet associated with the Eta Lyrids is IRAS-Araki-Alcock, which was seen in early May of 1983. Although it didn't have much of a tail, its coma was over two degrees in diameter, and was about 1.5 magnitude in brightness. It was easy to see with just the unaided eye. It was discovered near the head of Draco, and moved several degrees per day across the northern sky. It was the closest known approach a comet has made to Earth since Comet Lexell in 1770. A meteor shower associated with it was predicted soon after its discovery by American astronomer Jack Drummond of Stewart Observatory [Kronk C&MS].
Anyway, on May 10th, 1983, the predicted date of maximum for the possible meteor shower predicted by Drummond in the IAU Circular 3801 for this comet, a few amateur astronomers noted moderate activity from this putative radiant. Most of these observers were from Japan. I also noted unusual meteor activity at that time, and reported it to Sky & Telescope along with a drawing of the comet I made with my 6-inch f/12 reflector while visiting my parents in Chagrin Falls, Ohio. However, I had estimated the radiant was more near the head of Draco. These meteors were known as the IRAS-Araki-Alcockid's by some groups.
This meteor shower was thought to be temporary, and was soon forgotten by most meteor groups. However, several years later, members of the Dutch Meteor Society reported modest activity from this radiant. Alerted by this, members of the American Meteor Society (AMS) were notified by Robert Lunsford, the AMS Visual Coordinator, to watch for these meteors in 2002.
I was able to see moderate activity from the Eta Lyrids in 2002 and again in 2005. NAMN observers have reported some activity every year since 2002. This seems to be a newly created annual minor meteor shower! This shower has finally been recognized by the IMO (International Meteor Organization), and is included in their Working List of Visual Meteor Showers, online at http://www.imo.net/calendar/2007. It was also finally recognized by the American Meteor Society this past year too.
It is rare to see the actual birth of a new annual meteor shower just after seeing the parent comet coming close to Earth. In fact, I can't think of this ever happening before. So, it is truly a once in a lifetime experience. Also, fun to think that it was the watchful eyes of amateur astronomers that led to the discovery of the Eta Lyrids.
Now we can look to the stars near Eta Lyra every May 9th or so, and every year still see pieces of Comet IRAS-Araki-Alcock, and remember seeing that big tailless comet that amazed us back in May of 1983 as it sailed across our northern springtime skies...
(George Gliba has been an active meteor observer for many years, supporting all of our meteor community. A biographical sketch of this dedicated observer can be found at http://www.amsmeteors.org under 'AMS Observer Profiles'. Comet IRAS-Araki-Alcock was found independently by the InfraRed Astronomical Satellite, Genichi Araki of Japan, and George Alcock of England. Araki used a 3" refractor. Alcock used 15x80 binoculars looking through a double glazed upstairs window. An inspiring write-up on comets and Alcock can be found at http://news.bbc.co.uk/1/hi/sci/tech/1081747.stm. To see what comets are now visible in our skies, visit http://www.skyhound.com/sh/skyhound.html)
The eta Lyrids (ELY) reach a peak on May 9th, at about 12h UT, and can be seen from about May 3rd to 12th. This is a shower new to the IMO 'Working List of Visual Meteor Showers', and is debris from Comet IRAS-Araki-Alcock. These are average velocity meteors at about 44 km per second, with ZHR rates about 3 meteors per hour. The radiant at maximum will be at 287 degrees, ie. RA 19h 7.8m, Dec +44. If you draw a line between Vega and the top wing star of Cygnus (delta), the radiant is about 2 degrees north of the midpoint.
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 May 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 May'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 observers interested in observing meteor showers using radio equipment, we have the following peak dates for radio listening. More info can be found on the IMO website at http://www.imo.net
Epsilon-Arietids May 9 20h UT May Arietids May 16 21h UT o-Cetids May 20 19h UT
Planets at midmonth, and their magnitudes, for northern observers, are:
Venus -4.0 in west in early evening sky Jupiter -2.5 in Ophiuchus Saturn 0.4 in Leo
Saturn will be very close to the moon in the sky on May 22nd (0.8 degrees south), with an occultation visible from Europe, the British Isles, NW Canada, NE Africa, NW Asia, and the Arctic.
Note also that meteor observers will be able to see the asteroid Vesta with the unaided eye for about 2 months, from May 1st to June 30th (magnitude 6.0 those dates), with a peak brightness at about magnitude 5.4 on May 30th. On May 30th, it will be at RA 16h 33.5 Dec -14 02. Finder charts for 2007 are available at http://www.rasnz.org.nz under 'Bright Asteroids'.
The phases of the moon for May are as follows:
Wed. May 2 full moon Thurs. May 10 last quarter Wed. May 16 new moon Wed. May 23 first quarter
A useful monthly moon calendar for May can be printed off from http://stardate.org/nightsky/moon
For kids (of all ages), the NASA color space calendar can be printed off from 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
Lastly, for great printable all-sky charts, check out 'Heavens Above' at http://www.heavens-above.com. Ignore the 'Register' bit. Just 'Select' your country, then your city, and then scroll down the page to 'Whole Sky Chart'. Type in what day you want, and pick a time of night. Pick black on white as it's easier to read and print off. The maps show the constellations and the positions of all the visible planets. 'Heavens Above' also gives the times you can see the ISS, the International Space Station, pass over your home or observing site. And - if you note the times and paths of any satellites you see while meteor observing, you can use 'Heavens Above' after your meteor session to find out what satellites they were!
June 7-10, 2007, Bareges, France...
The International Meteor Conference (IMC) of the IMO will be held in Bareges, France from June 7th to 10th. It is being organized jointly by the IMCCE, Institut de Mecanique Celeste et de Calcul des Ephemerides, the Paris Observatory, the Observatoire Midi-Pyrennees and AUDE, l'Association des Utilisateurs de Detecteurs Electroniques. This is a gathering for both amateur and professional meteor observers - and a wonderful opportunity to meet observers from all around the globe. Accommodation will be at l'Hospitalet, with talks at the nearby village cinema. The registration fee is 120 EUR before May 1st, 130 EUR after. The fee includes the conference, all your accommodation, all your meals, a special excursion to visit the Pic du Midi Observatory in the Pyrenees - and a conference t-shirt. For radio observers, there will be a Radio Meteor School just prior to the IMC conference. For more info, check out the conference website at http://www.imo.net/imc2007
June 11-15, 2007, Barcelona, Spain...
The Meteoroids 2007 conference will be held from June 11th to 15th at the
CosmoCaixa Museum in Barcelona, Spain, organized by the Institut d'Estudis
Espacials de Catalunya.
The preliminary scientific program includes the following sessions:
1. Observational techniques and meteor detection programs
2. Meteor showers' activity and forecasting
3. Orbits of meteoroids and dust
4. Meteoroids' interactions with atmospheres
5. Atmospheric effects induced by meteors
6. Astromineralogy: properties of meteoroids
7. Interrelationships: meteoroids - IDPs - dust - micrometeorites -
meteorites
8. Meteoroid flux and impact hazard
9. Meteor studies in astrobiology
Invited speakers include Diego Janches, Pavel Spurny, Douglas ReVelle, Peter Brown, Jeremie Vaubaillon, Junichi Watanabe, Peter Jenniskens, P.A. Wiegert, I. Williams, Olga Popova, Lars Dyrud, John Plane, Nick Mitchel, Frans J.M. Rietmeijer, Jiri Borovicka, George Flynn, Matthew Genge, Donald Yeomans, Clark Chapman, M.E. Sansaturio, Jose Ortiz, Joseph A. Nuth III, Josep M. Trigo-Rodriguez, and Alessandra Rotundi.
For more information, check out the Meteoroids 2007 website at http://www.spmn.uji.es/meteoroids-2007, or contact Dr. Josep M. Trigo-Rodriguez at trigo@ieec.uab.es.
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
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Contact Lew Gramer at:
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