(meteorobs) NAMN Notes: June 2007
Mark Davis
meteors at comcast.net
Mon May 28 16:55:12 EDT 2007
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NAMN Notes: June 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. 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...
1. June and the Bootid Meteors...
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 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
2. Other June Meteor Activity...
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 June 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
3. Lyrids Put on Good Show for a Lonely Observer... by Wayne T. Hally
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 at eclipse.net - just put 'NAMN' in the
subject line.)
4. Astronomical Info Sheets...
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 at 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.
5. Upcoming Meetings...
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 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 listed 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, Clark Chapman, M.E.
Sansaturio, Jose L. 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 at 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 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 the NAMN Coordinator and let us know!
6. 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
==============================================
Here's to 'Clear Skies' for June...
June 2007 NAMN Notes
written by Cathy Hall & edited by Mark Davis
==============================================
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