(meteorobs) NAMN Notes: July 2007

Mark Davis meteors at comcast.net
Wed Jul 4 11:50:13 EDT 2007


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NAMN Notes:  July 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.  Time Passages and Meteor Friends...
2.  Aquarids for the Summertime...
3.  Other July Meteor Activity...
4.  Upcoming Meetings...
5.  For more info...


1.  Time Passages and Meteor Friends...

In these past weeks our meteor community has heard about several more
observers who have 'slipped the bonds of earth' and passed away.

We would like to extend our condolences to their families - and to all those
in our meteor community who have lost loved ones.  We usually keep our
conversations on topic and about meteors - and there may be others who
have recently passed away that we have not heard about.

Our sympathies go out to veteran Florida meteor observer Norman McLeod, on
the passing of his wife and observing partner, Joan.

Our sympathies also go out to the family of Stan Mott, a Canadian observer
who was a member of Dr. Peter Millman's Springhill meteor team.

Many of us met Joan at the NAMN gathering in West Virginia back in 1998.
She was a delightful and intelligent lady, and observed with Norman for many
years.

Stan Mott was with Dr. Millman for the 1946 Giacobinid expedition - and we
wrote up his meteor experiences in our NAMN Notes back in 1998.  Our amateur
meteor group in Ottawa knew Stan well.  He was always there to encourage our
meteor pursuits.

Astronomy has been a comfort, and an inspiration, for so many of us.  We
look to the skies to learn, and we look to the skies for comfort in times of
need.  We hope that the skies provide that comfort for these families...

The French astronomer Camille Flammarion expressed that sentiment in his
writings of 1903:

"It is indeed difficult to resist a sense of profound emotion before the
abysses of infinite space, at the sight of the innumerable multitude of
worlds above our heads.  We feel in this solitary contemplation of the
heavens that there is more in the universe than tangible and visible matter:
that there are forces, laws, destinies.  Our... brains may know themselves
microscopic, and yet recognize that there is something greater than the
earth, the heavens; - more absolute than the visible, the invisible; -
nobler than the common business of life, the conviction of beauty, of truth,
and of good.  We feel that an immense mystery broods over nature - over all
human beings, over created things..."

"O night, mysterious, sublime, and infinite!  withdrawing from our eyes the
veil spread above us by the light of day, giving back transparency to the
heavens, showing us the prodigious reality, the shining casket of the
celestial diamonds, the innumerable stars that are set in the immeasurable
distances of space!  Without you we should know nothing..."

"O sacred night!  If on the one hand you rest upon the heights of truth
beyond the day's illusions, on the other your invisible urns pour down a
silent and tranquil peace, a penetrating calm, upon our souls that weary of
life's troubling; you make us forget struggles, deceptions, intrigues, the
miseries of the hours of toil...  Your domain is that of rest and dreams..."


2.  Aquarids for the Summertime...

Summer is upon us again.  It's hard to believe that we're already halfway
through the year.  For those of us in northern climes, we could have snow in
just over 3 months time.  That sounds like excellent motivation for
tolerating warm nights and hungry mosquitoes in our quest for meteors...

Aquarius?  If you aren't already familiar with the constellation, get used
to it now.  We have a lot of summer meteors coming from Aquarius.  It's
often a hard constellation to make out if you are under light-polluted
skies, but its pattern in the sky emerges as you travel to a darker site.

What's the pattern?  Take a look at the star map by the SEDS group at
http://messier.obspm.fr/map/Aqr.html.  If you'd like to see a map of
Aquarius, with Aquarius himself against the stars, check out Jan
Wisniewski's website at http://www.astrosurf.com/jwisn/aquarius.htm.  The
mythical outline is based on Johannes Hevelius' Uranographia (1690).  For
the legends behind the constellation of Aquarius, check out the New Jersey
website at http://www.ufrsd.net/staffwww/stefanl/myths/aquarius.htm

The southern delta Aquarids (SDA) reach a maximum on July 28th with a
radiant at 339 degrees, ie. RA 22h 36m, Dec -16, which is about 5 degrees to
the right of the star delta Aquarius.  They can be seen from about July 12th
to August 19th.  For a map showing the radiant and its motion from night to
night, check out the website of the International Meteor
Organization (IMO) at http://www.imo.net/calendar/2007

The SDA's are average velocity meteors at about 41 km/sec.  At the peak on
July 28th, ZHR rates are about 20 meteors per hour.

What is ZHR?  This is Zenithal Hourly Rate and is the number of meteors on
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 radiant is higher in the sky.

This shower is rich in faint meteors, but also has brighter meteors as well.
The IMO also mentions that "radio work can be used to pick up the SDA... and
indeed the shower can sometimes give a surprisingly strong radio signature."
For info on what's involved in observing meteors by radio, more information
can be found on their website at http://www.imo.net

We have a change in Aquarid meteors for this year though.  NAMN follows the
"Working List of Visual Meteor Showers" put out by the International Meteor
Organization.  In previous years, the IMO listed north and south delta
Aquarids (NDA and SDA), and north and south iota Aquarids (NIA and SIA).  No
longer.  Now we have just the SDA meteors.  The IMO provides more info in
their 2007 Meteor Shower Calendar:

"Fresh investigations of the near-ecliptic Aquarid and alpha-Capricornid
(CAP) streams using IMO and other visual and video data...  have generally
confirmed the known details for the stronger Southern delta-Aquarid (SDA)
and CAP maxima, but the SIA and NIA did not appear at all clearly,
unsurprising given their borderline-visible ZHRs.  The greatest oddity was
the NDA, for which no distinct maximum could be traced, and whose ZHRs were
never better than ~ 3.  A recent investigation of the ecliptical radiants
showed that what was regarded as the NDA radiant is in fact entirely within
the radiant area of the Antihelion Source...  The showers SIA, NIA, and NDA
are no longer included in the new Working List for 2007."

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

So - we no longer need to watch for these other (previously monitored)
Aquarid meteors.  However, plotting is still encouraged for the south delta
Aquarids, the Antihelion meteors, and the alpha Capricornids (discussed in
the next section), as they all originate in the same general area of the
sky.

If you want to help record visual data for the meteor researchers,
check out the 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

For those of you interested in plotting your meteors (recommended for
serious observations), special IMO plotting maps can be ordered through
Robert Lunsford of the International Meteor Organization. For details,
contact him directly at lunro.imo.usa at cox.net


3.  Other July Meteor Activity...

The June Bootids (JBO), although having peaked June 27th, are visible until
about July 2nd. These are slow meteors with a velocity of about 18 km/sec.
ZHR rates are variable. A map showing the radiant is available at
http://www.imo.net/calendar/2006/spring

Several other July showers that were previously on the IMO Working List are
also missing from the 2007 list:  the Pegasids (JPE) and the July Phoenicids
(PHE).  When activity has been low over an extended period of time, the IMO
will often remove a shower from their current Working List.  The IMO Meteor
Shower Calendar is prepared "as a means of helping observers deal with
reality by highlighting times when a particular effort might most usefully
be employed."

The Pisces Austrinids (PAU) peak about July 28th but can be seen from about
July 15th to August 10th.  These are average velocity meteors at about 35
km/sec.  The radiant at the peak will be at 341 degrees, ie. RA 22h 43.8m,
Dec -30, which is about 3 degrees to the right of alpha Pisces Austrinus,
the star known as Fomalhaut.  ZHR rates are about 5 meteors per hour at
maximum.  For a map showing the movement of the radiant, check out
http://www.imo.net/calendar/2006/summer

The alpha Capricornids (CAP) peak about July 30 and range from about July
3rd to August 15th.  These are wonderful, slow meteors, with a velocity of
about 23 km/sec.  On July 30th, at maximum, the radiant will be at 307
degrees, ie. RA 20h 28.2m, Dec -10, which is about 3 degrees up to the left
of the star alpha Capricornus, the top right star of the triangle of
Capricornus.  ZHR rates at the peak are about 4 meteors per hour.  For
movement of the radiant, check out the map on the IMO website at
http://www.imo.net/calendar/2007.  According to the IMO in their annual
Meteor Shower Calendar, the alpha-Capricornids "are noted for their bright -
at times fireball-class - events, which, combined with their low apparent
velocity, can make some of these objects among the most impressive and
attractive an observer could wish for."

Lastly, although observers tend to think of Perseids (PER) as an August
shower, they start to become active about July 17th.  They run through until
about August 24th, with a peak around August 13th.  These are fast meteors
with a velocity of about 59 km/sec.  ZHR rates around August 13th will be
about 100 meteors per hour.  Rates in July will be much lower.  This shower
lasts a long time - and the radiant moves quite a distance across the sky, a
little bit each night.  Check out this movement on the IMO chart at
http://www.imo.net/calendar/2007

For other July 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 July'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.

The magnitudes of the planets just before mid-month are as follows:
Venus      -4.3
Jupiter    -2.5
Saturn      0.6
Mars        0.6

For a sky chart showing the positions of these planets in July,
go to http://www.heavens-above.com, 'Select' your country, type in the name
of your nearest city, and then go to 'Whole Sky Chart'.  Pick 'black on
white' before printing.  The 'Heavens Above' website will also tell you when
to look to see the ISS, the International Space Station, go over your
observing site.

The phases of the moon for July are as follows:
Sat.   July  7    last quarter
Sat.   July 14    new moon
Sun.   July 22    first quarter
Mon.   July 30    full moon
On July 16th, Saturn will be 0.04 degrees north of the moon, with an
occultation visible in Hawaii, and western parts of South America.

For phases of the moon, a great monthly moon calendar can be printed off
from http://stardate.org/nightsky/moon.  For the NASA kids' calendar for
July, go to 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 some great sky maps showing not only the stars, but the ancient
mythical drawings superimposed, check out Jan Wisniewski's website at
http://www.astrosurf.com/jwisn/constellations.htm


4.  Upcoming Meetings...

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

August 13-17, 2007, Tucson, Arizona, U.S.A...

The 70th Annual Meeting of the Meteoritical Society will be held in Tucson,
Arizona.  Special sessions will be held on meteor craters and impacts,
chondrules and chondrule formation, protoplanetary dust, and the study of
cosmogenic radionuclides, with other sessions on meteorites, asteroids and
comets, and high and low temperature parent body processes.  A 3-day
post-conference field trip will be held to the Barringer Meteorite Crater,
Sunset Crater Volcanic National Monument, and the Grand Canyon.  For
information, contact Elizabeth Wagganer of the Lunar and Planetary Institute
at wagganer at lpi.usra.edu and check out the conference website at
http://www.lpi.usra.edu/meetings/metsoc2007

Note:  check out the online abstracts for the conference at
http://www.lpi.usra.edu/meetings/metsoc2007/metsoc2007.authorindex.shtml.
Click on the 4-digit code to read the ones that interest you...

September 6-9, 2007, Ivy, Ontario, Canada...

HSP 2007, the Huronia Star Party, a small but growing amateur 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 our NAMN Coordinator and let us know!


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

==============================================
Here's to 'Clear Skies' for July...

July 2007 NAMN Notes
written by Cathy Hall & edited by Mark Davis
==============================================





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