(meteorobs) NAMN Notes: May 2007

Tue May 1 19:52:52 EDT 2007

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NAMN Notes:  May 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.  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...

1.  Eta Aquarids - Comet Halley and the Meteors...

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 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.  Watching the Birth of a New Meteor Shower - by G.W. Gliba...

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)

3.  Other May Meteor Activity...

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!

4.  Upcoming Meetings...

June 7-10, 2007, Bareges, France...

The IMC, the International Meteor Conference of the International
Meteor Organization, 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, 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.

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

5.  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

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Here's to 'Clear Skies' for May...

May 2007 NAMN Notes
written by Cathy Hall & edited by Mark Davis
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