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. June and the Bootid Meteors...
2. Other June Meteor Activity...
3. Lyrids Put on Good Show for a Lonely Observer... by Wayne T. Hally
4. Astronomical Info Sheets...
5. Upcoming Meetings...
6. For more info...
The June Bootids (JBO) reach a peak on June 27th with an estimated peak time of 20h UT, according to the International Meteor Organization (IMO). UT refers to Universal Time, and is the time at Greenwich, England. These meteors can be seen from about June 22nd through until about July 2nd.
The June Bootids are debris from Comet 7P/Pons-Winnecke. This comet was discovered from Marseilles, France on June 12, 1819 by the famous comet hunter Jean Louis Pons. It was considered lost after this - and then was rediscovered on March 9th, 1858 by Friedrich August Theodor Winnecke of Bonn, Germany. Both names were adopted for the comet once it was realized that both sightings were of the same body.
The meteor shower was first noted in the spring of 1916. According to A.C.B. Lovell in his book "Meteor Astronomy":
"A very sharp maximum seems to have occurred on 1916 June 28, which was seen by observers in England but not in America. Denning gave the rate as 32 per hour, but other observers gave 100 per hour, whereas in America the rate did not exceed 6 per hour. Olivier gives details of the low hourly rate of meteors belonging to this shower from 1916 May 20 to July 10. The disparity in the rates observed in England and America on June 28 indicates that the dense part of the swarm must have been extremely localized..."
On Gary Kronk's 'Meteor Showers Online' website, Kronk quotes Denning's observations:
"Large meteors came in quick succession from a radiant in the region between Bootes and Draco... moderately slow, white with yellowish trains, and paths rather short in the majority of cases. Several of the meteors burst or acquired a great intensification of light near the termination of their flights, and gave flashes like distant lightning."
The ZHR, Zenithal Hourly Rate, for the June Bootids is variable. ZHR refers to the number of meteors, on average, that an observer would expect to see if they are out under a dark country sky, and if the radiant of the shower, the area in the sky where the meteors seem to come from, is directly overhead. Kronk's website talks about Russian observers reaching hourly rates of about 500 meteors per hour on June 27th, 1927, and high rates being seen by a Japanese observer as late as July 3rd to 5th in 1921.
In 1998 there was an outburst with ZHR rates ranging from 50 to over 100 meteors per hour visible for over half a day. Another outburst occurred in 2004 on June 23rd with ZHR rates of about 20 to 50.
The radiant for the June Bootids on June 27th will be at 224 degrees, ie. RA 14h 55.8m, Dec +48, which is about 8 degrees north of the star beta Bootes, the star called Nekkar. These are slow meteors, with a velocity of about 18 km per second, so will be quite distinctive. A map of the radiant can be found on the IMO website at http://www.imo.net/calendar/2006/spring
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
The June Lyrids (JLY) reach a peak about June 16th, and are visible from about June 11th to 21st. These are average velocity meteors at about 31 km per second. The ZHR rate is listed as variable, 0-5 meteors per hour. Plotting is encouraged. According to the IMO "in 1996, several observers independently reported some June Lyrids, though no definite activity has been found subsequently." All observations are encouraged to see if there is any activity this year. A map of the radiant can be found on the IMO website at http://www.imo.net/calendar/2004/spring
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 June 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
Some of the minor showers listed on Kronk's website include the Tau Herculids, with a maximum around June 9/10 and a radiant at 236 degrees, ie RA 15h 43.8m, Dec +41; the Ophiuchids with a maximum around June 20/21 and a radiant at 263 degrees, ie. RA 17h 31.8m, Dec -20; and the June Scutids with a maximum around June 27/28 and a radiant at 278 degrees, ie RA 18h 31.8m, Dec -4. Minor shower activity is generally noticed only by detailed plotting by experienced observers.
Besides June'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 radio meteor observers, the theoretical daylight shower peak times are as follows:
Arietids June 7 23h UT zeta Perseids June 9 22h UT beta Taurids June 28 21h UT
Kronk's website lists the Arietids as "the strongest daylight meteor shower of the year... from RA=44.5 deg, DECL=+23.6 deg. The hourly rate is near 60 at maximum." This corresponds to a radiant at RA 2h 58.2m, Dec +23.6. He gives the average radiant of the zeta Perseids as 63 degrees, ie RA 4h 12m, Dec +26, and the average radiant of the beta Taurids as 79.4 degrees, ie RA 5h 17.4m, Dec +21.2. For info on how to observe radio meteors, check out the IMO website at http://www.imo.net. According to the IMO, the Arietid and zeta Perseid maxima may occur up to a day later than the theoretical peaks.
The magnitudes of the planets just before mid-month are as follows:
Venus -4.2 in evening sky Jupiter -2.6 in Ophiuchus Saturn 0.5 in Leo Mars 0.8 in Pisces Mercury 1.5 in early evening 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 June are as follows:
Fri. June 1 full moon Fri. June 8 last quarter Fri. June 15 new moon Fri. June 22 first quarter
Note that Venus will be about 0.6 degrees south of the moon on June 18th, with an occultation visible from western Asia, the British Isles and Europe, Greenland and northern Canada. On June 19th, Saturn will be about 0.4 degrees south of the moon with an occultation visible from Japan, central Asia, and the eastern part of Europe.
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
The Lyrids are the first major meteor shower of the season, and are much appreciated after the cold days of winter. This year the weather gods cooperated with clear skies and mild temperatures, while the debris of Comet C/1861 G1 (Thatcher) provided a pleasantly high rate of meteors, much as last year's Orionids did.
I was able to observe for two nights (more accurately, mornings) leading up to the peak, and during the morning afterward, when rates were much better than expected.
On the morning of the 21st of April, I watched from 2:40-4:33 a.m. EDT. During these 1.82 hours of Teff (effective observing time, subtracting time for plotting non-Lyrids), I only recorded 1 Lyrid under LM (Limiting Magnitude) skies of +5.35. That was a bit disappointing, but not surprising, considering the hazy skies and low Lyrid rates at that time, 1 1/2 days before the expected peak. I also plotted 4 sporadic meteors, for a total rate of only 2.7 meteors per hour. Not for the faint hearted!
The first 1.28 hours Teff on the morning of the 22nd (0215-0334 EDT) were equally as disappointing, with only 1 Lyrid, 1 sporadic, and 1 from the ecliptic meteor source (ANT for antihelion) in Libra. However, the final period, 1.30 hours Teff from 0334-0453 EDT, was much better, raising some hopes. I counted 5 Lyrids and plotted 2 sporadics. The sky was much better - my measured LM was +5.60 for the morning. For the second period, my calculated ZHR (Zenithal Hourly Rate) for the Lyrids was almost 10. With the peak still half a day away, that's about as expected. Overall, I saw 3.9 meteors per hour.
The predicted peak of this year's Lyrids was at about 6:30 p.m. EDT on the 22nd, so was not observable from the U.S. The IMO (International Meteor Organization) online reports indicated that the peak (visible from Europe) occurred at Solar Longitude 32.340, or about 7:05 p.m. EDT (2305 UT Apr 22). The ZHR was 21 +/-3 meteors per hour. There were many reports from Europe, which provided sufficient data to define the peak ZHR and time within a half hour or so.
Here on the other side of the pond, the hours following the peak were only reported by two people - Pierre Martin, west of Ottawa, and me at the NJAA. Pierre is an old friend from the North American Meteor Network. (He and Cathy Hall actually drove from Ontario down to New Jersey to observe the 1998 Leonids.) Unfortunately, I was the only one recording scientific data during what may have been an unanticipated Lyrid outburst. Seduced by a telescope, Pierre did not start until later (0220 EDT).
(Editor's note: A number of years back, Lew Gramer commented that all meteor observations are very valuable - as you never know when you might be the only person out observing that night... Even experienced meteor observers who provide meteor data on a regular basis can sometimes miss a night - or miss an outburst. This is why our meteor community needs all observers - if you can only manage a couple hours from time to time, your observations are still extremely valuable!)For the first hour (0.97 Teff, Apr 23, 0023-0123 EDT) the moon was still up, and my measured LM was only +5.35, about like the first night. I only counted 2 Lyrids, and plotted 2 sporadic meteors.
But then things picked up! Once the moon set, my LM ranged between +5.55 and +5.70, about as good as it gets for me at the NJAA Observatory. Over the next 2 3/4 hours of Teff (0123-0408 EDT), I recorded 24 Lyrids. The EZHR (Equivalent ZHR, for periods less than an hour) peaked around 35 meteors (!) for the half hour from 0153-0223 EDT. This was totally unexpected.
To add to the fun, I also plotted a -3 magnitude sporadic, and another meteor that may have been an eta Aquarid (from Halley's Comet), with the radiant below the horizon, nearly impossible! Had I not plotted that meteor, I wouldn't have even been able to consider that as a possibility.
For the whole morning, I counted 28 Lyrids in 4.30 hours Teff (0023-0453 EDT), as well as 1 ETA (eta Aquarid), 2 ecliptic meteors, and 7 sporadics, for an average of 8.8 meteors per hour. Not too bad.
So, did I catch an outburst? One person's observations cannot prove that, but it sure seems unusual. Hopefully, other people were watching and will report additional data, so mine can be confirmed. If not, it will stand alone in the IMO database as a possibility. This is one reason I promote meteor observing as an area where the trained amateur astronomer can provide useful scientific information. The more observers, the better! Much of the progress that has been made during the last decade in understanding and predicting meteor showers, storms, and outbursts could never have happened without dedicated amateur observers like me - and hopefully, you. Meteor showers are like a box o' chocolates... you never know what you will get unless you watch.
HALWA at NJAA Observatory (New Jersey, U.S.)
DATE UT TIME Teff LM LYR ANT ETA SPO TOT LYR ZHR ____________________________________________________________ Apr 21 0640-0833 1.82 +5.35 1 0 0 4 5 4 +/-4 -------- Apr 22 0615-0734 1.28 +5.58 1 1 - 1 3 4 +/-4 Apr 22 0734-0853 1.30 +5.62 5 0 0 2 7 10 +/-5 -------- Apr 23 0423-0523 0.97 +5.35 2 0 - 2 4 11 +/-8 Apr 23 0523-0553 0.50 +5.55 5 0 - 0 5 28 +/-13 Apr 23 0553-0623 0.42 +5.60 6 1 - 3 10 35 +/-14 Apr 23 0623-0653 0.48 +5.70 3 0 1 0 4 14 +/-8 Apr 23 0653-0723 0.46 +5.60 5 1 0 1 7 24 +/-11 Apr 23 0723-0808 0.72 +5.67 5 0 0 1 6 15 +/-7 Apr 23 0808-0853 0.75 +5.55 2 0 0 0 2 7 +/-5 Meteor Magnitudes DATE Shower -3 -2 -1 0 1 2 3 4 5 Avg. ______________________________________________________________ Apr 21 LYR 0 0 0 0 1 0 0 0 0 0.0 Apr 21 Spo 0 0 0 0 1 1 1 1 0 +2.5 -------- Apr 22 LYR 0 0 0 0 0 0 4 1 1 +3.5 Apr 22 ANT 0 0 0 0 0 0 0 1 0 +4.0 Apr 22 Spo 0 0 0 0 0 1 1 1 0 +3.0 -------- Apr 23 LYR 0.5 0.5 3.5 2 5 4 5 7 0.5 +1.9 Apr 23 ETA 0 0 0 0 1 0 0 0 0 +1.0 Apr 23 ANT 0 0 0 1 1 0 0 0 0 +0.5 Apr 23 Spo 1 0 0 0.5 0.5 0 0 4.5 0.5 +2.6 NAMN data suitable for analysis DATE UT Time ~Sol Long Observers Teff LYR ANT ETA SPO ________________________________________________________________ Apr 21 0640-0833 30.7 1 1.82 1 0 0 4 Apr 22 0330-0915 31.7 4 13.58 55 16 0 55 Apr 23 0620-1048 32.7 3 8.45 64 6 1 48(Editor's note: Wayne Hally has provided a wonderful graph showing the Lyrid meteor rates. As we do not send attachments with our newsletter, please check out our online version of the graph at http://www.namnmeteors.org/ANlyrids.htm)
The graph shows my hourly calculated Lyrid ZHR (large triangles), as well as Pierre's (asterisks), other North American observers' ZHR's (+'s), and the NAMN average for the entire U.S./Canada window. My hourly calculated Lyrid ZHR is clearly higher than the measured peak during the evening, and even Pierre's rates are higher than expected, aligning close to mine after the outburst (?) occurred.
Notes for the graph:
The IMO data comes from http://www.imo.net/live/lyrids2007. This includes only data reported to the IMO via their online form. Further reports will come in by other means, and if it is deemed suitable for further analysis, a report may be issued in WGN, the IMO journal - but that will be months from now. The online reports include 34 observers from 14 countries, only 2 from the U.S., and one each from Canada and Mexico. This article includes data submitted through May 14th.
The NAMN data are North American reports that were submitted to the MeteorObs email list. They include observations from Pierre Martin in Ottawa, Kim Youmans in Georgia, Paul Martsching in Iowa, Wes Stone in Oregon, and George Gliba in West Virginia, all experienced meteor observers. Eventually, those records will be included in the IMO's VMDB (Visual Meteor Data Base). These show as "+" on the graph, except for Pierre, whose rates are displayed as asterisks. Those were the observers who provided enough information to calculate a ZHR. That information is: Location, Time of Observation, Teff, Number of Lyrids, and Limiting Magnitude. On the NAMN website at http://www.namnmeteors.org, all observations (including those with insufficient information, and those outside the continent) are included in the 'Recent Meteor Observations' section.
The time axis for the graph is in Solar Longitude: 31.2 is about 19h UT on the 21st, 32.8 is about 11h UT on the 23rd of April. My peak EZHR (35 meteors) occurred at about 32.626 (2:08 a.m. EDT Apr 23); my hourly ZHR on the graph (31 meteors) is at 32.616, lower (~31) since it consists of hourly averages, not the half hour periods. The NAMN Avg is the weighted average of all North American observations between the periods when the IMO had sufficient observations from Europe.
Coverage was sparse in the U.S. and Canada, particularly at the time I observed the potential outburst. Clouds wrecked the chances for folks in the southwestern U.S.. I guess, if it's just me, that should be considered sparse! Hopefully, I'll be able to inspire future observers, both here at the NJAA, and across the U.S....
(Wayne Hally holds down North American skies from High Bridge, New Jersey, U.S.A. For questions on meteors and how to get involved in gathering useful data, he can be reached at meteors@eclipse.net - just put 'NAMN' in the subject line.)
Need some info sheets on meteors and what's up in the sky - for the public, or your local astronomy club, or for your kids' school or scout groups?
NAMN has a number of printable astronomical info sheets available. These are updated by Cathy Hall every spring, with the current year's meteor shower information, and all updated web links:
1. "How to Observe Shooting Stars" - our tri-fold, 2-sided NAMN brochure
2. "What are Meteors?" - a 1 page info sheet on showers throughout the year
3. "What is a Meteor?" - a French info sheet, with thanks to Pierre Martin
4. "Surf the Astro Web!" - a list of recommended astronomy websites
5. "What's Up Tonight?" - how to find out what's visible in tonight's sky
These info sheets are available in electronic form at no charge - just email Lew Gramer, our Public Outreach Coordinator at dedalus@alum.mit.edu, or any of the rest of us, addresses at the end of the newsletter. The info sheets are in Word format, and you can just print off as many copies as you need for your group.
June 7-10, 2007, Bareges, France...
The International Meteor Conference (IMC) of the International Meteor
Organization (IMO), will be held in Bareges, France from June 7th to 10th.
It is being organized jointly by the Institut de Mecanique Celeste et
de Calcul des Ephemerides (IMCCE), the Paris Observatory, the Observatoire
Midi-Pyrennees and l'Association des Utilisateurs de Detecteurs
Electroniques (AUDE). 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 130 EUR for those signing up
now. 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 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.
August 9-13, 2007, Mount Forest, Ontario, Canada...
Starfest 2007, Canada's largest amateur astronomical observing convention,
will be held at the River Place Campground, near Mount Forest, Ontario.
This year's theme is 'The Universe in Motion' - and covers many different
fields of astronomy. There will be a panel discussion on 'McNaught: The
'Tail' of a Great Comet', chaired by well-known astronomy writer Terence
Dickinson. On meteors, there will be a talk by Dr. Peter Brown of the
University of Western Ontario Meteor Physics Group on the 'Southern Ontario
Meteor Network'. Details on all the many speakers, and convention info, can
be found online at
http://www.nyaa-starfest.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