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(meteorobs) NAMN Notes: July 2002



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NAMN Notes:  July 2002
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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. Lots of Aquarids in July...
2. All the Other Showers to Watch for...
3. Summer Reading for Meteor Enthusiasts...
4. Upcoming Meetings...
5. For more info...


1.  Lots of Aquarids in July...

Summer is a busy season for meteor observers, and in July, the meteors
really start to fly!

If you are already familiar with the summertime night sky, you are starting
well-prepared.  If you are just starting out in meteor observing, print off
a set of NAMN star charts from http://www.namnmeteors.org/charts.html  These
charts will help teach you the constellations, give you some standard stars
to judge the brightness of the meteors you see, and also give you some maps
to mark your meteor radiants on.  What are radiants?  Every meteor shower
has an area in the sky where their meteors seem to come from - this area is
called the radiant.

The best shower for the month of July is the southern delta Aquarids (SDA),
reaching maximum activity 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.  RA and Dec are coordinates in the sky - look at the edges of our
NAMN star maps and you will see them marked.  RA stands for Right Ascension,
and is like longitude in the sky.  Dec stands for Declination, and can be
compared to latitude.

The ZHR (Zenithal Hourly Rate), for this shower is about 20 meteors per
hour. This is the number of meteors that an observer would see, on average,
every hour if they were out under a dark country sky (no lights, no moon),
and if the radiant, the area in the sky where the meteors seem to come from,
is directly overhead.  Thus - to see more meteors, wait until the radiant is
high in your sky, and get away from city lights!

These are average velocity meteors, at about 41 km per second.  Meteors come
in all velocities.  Once you've been out observing for a while, you will be
able to tell the difference between slow, medium and fast meteors.

The southern delta Aquarids can be seen from about July 12th to August
19th - and their radiant moves over this time period.  For a map showing
this movement, check out the website of the International Meteor
Organization (IMO) at http://www.imodot net/calendar/cal02.html#Aquarids


2.  All the Other Showers to Watch for...

If you haven't already printed off a set of our four NAMN star charts, now
would be a good time.  Set your printer to landscape mode, and go to
http://www.namnmeteors.org/charts.html

The summer sky is full of meteor showers.  In fact, it is hard to keep track
of them all.  Mark the various radiants on your maps and it will help you a
lot!

If you want to try helping out the meteor researchers by recording data on
the meteors you see, check out our NAMN Observing Guide at
http://www.namnmeteors.org/guide.html

The June Bootids (JBO), although reaching a maximum on June 27th, can be
seen until about July 2nd.  These are slow meteors, at about 18 km per
second, so would be quite distinctive.  They are debris from Comet
7P/Pons-Winnecke.  The number of meteors that can be seen is variable - back
in 1998, ZHR rates hit from 50 to over 100 meteors per hour for over half a
day.  Monitor this shower very carefully in late June and early July!  For a
map showing the location of the radiant, go to
http://www.imodot net/calendar/cal01.html#June-Bootids

The Sagittarids (SAG) last until about mid-July.  These meteors are believed
to be debris from a number of unknown bodies.  Sagittarids are almost
slow, with a velocity of about 30 km per second.  ZHR rates are about 5
meteors per hour.  Fireballs have been associated with this shower - so stay
alert!  The radiant of the Sagittarids follows along the path of the
ecliptic in the sky.  On July 10th, at new moon, the radiant will be at 293
degrees, ie. RA 19h 31.8m, Dec -22, which is about 5 degrees to the left of
the star pi Sagittarius on a star atlas.

The Pegasids (JPE) reach a maximum on July 9th, with a radiant at 340
degrees, ie. RA 22h 40.2m, Dec +15, which is about 4 degrees north of the
star zeta Pegasus.  At maximum, ZHR rates will be about 3 meteors per hour.
These are fast meteors, at about 70 km per second, and can be seen from
about July 7th to 13th.

The July Phoenicids (PHE) reach a maximum on July 13th, with a radiant at
032 degrees, ie. RA 2h 7.8m, Dec -48, which is about 27 degrees due south of
the star upsilon Cetus, the left foot of Cetus.  This shower is better
observed by those in southern latitudes.  Rates are variable.  These are
average velocity meteors, at about 47 km per second, and can be seen from
about July 10th to 16th.  Observations are encouraged by southern
observers - in their 2002 Meteor Shower Calendar, the IMO states that "more
data would be very welcome!"

The Pisces Austrinids (PAU) reach a maximum on July 27th, but can be seen
from about July 15th to August 10th.  ZHR rates will reach about 5 meteors
per hour at maximum.  These are average velocity meteors, at about 35 km per
second.  On July 27th, the radiant 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.

The alpha Capricornids (CAP) reach a maximum on July 29th.  These
are wonderful, slow meteors, with a velocity of about 25 km per second, and
are spectacular to see.  ZHR rates at maximum will be about 4 meteors per
hour.  They can be seen from about July 3rd to August 15th.  Early in the
month, on July 5th, the radiant will be at 285 degrees, ie. RA 19h 00m,
Dec -16, which is about halfway between lambda Aquila and sigma Sagittarius,
the star called Nunki.  At maximum on the 29th, the radiant will have moved
to 307 degrees, ie. RA 20h 28.2m, Dec -10, which is about 4 degrees up to
the left of the star alpha Capricornus, the top right star of the triangle
of Capricornus.

The southern iota Aquarids (SIA) start about July 25th, but won't reach
maximum activity until August 4th.  ZHR rates will be low in July, reaching
about 2 per hour by maximum.  These are average velocity meteors, at about
34 km per second.  On July 25th, the radiant will be at 322 degrees, ie. RA
21h 28.2m, Dec -17, which is very near the star iota Capricornus.  For a map
showing all the various Aquarid radiants - and their movement in the sky
over the next month - check out
http://www.imodot net/calendar/cal02.html#Aquarids

The northern delta Aquarids (NDA) start about July 15th, but won't reach
maximum activity until August 8th.  ZHR rates in July will be very low, and
even in August will only reach about 4 meteors per hour.  These are average
velocity meteors at about 42 km per second.  The radiant on July 15th will
be at 316 degrees, ie. RA 21h 4.2m, Dec -10, which is about 7 degrees due
north of the star theta Capricornus.  By July 30th, the radiant will have
moved to 327 degrees, ie. RA 21h 48m, Dec -8, which is about 8 degrees north
of delta Capricornus.  Using the coordinates, you can plot this on your NAMN
star charts - and should, as there are getting to be a lot of radiants to
keep track of!

Perseids (PER) start to become visible about July 17th, although won't reach
a maximum until August 12th.  ZHR rates in July will be low, but noticeable.
These are fast meteors, at about 59 km per second.  The radiant on July 20th
will be at 018 degrees, ie. RA 1h 12m, Dec +52, and by July 30th will have
moved to 029 degrees, ie. RA 1h 55.8m, Dec +55.  In constellation terms, on
July 20th the radiant is about 3 degrees south of the star theta Cassiopeia
and by July 30th will have moved to about 4 degrees up to the left of the
star phi Perseus.  A map showing the movement of the Perseid radiant during
July and August can be found at
http://www.imodot net/calendar/cal02.html#Perseids

Besides recognized main showers, and other minor showers, there is also
sporadic meteor activity in July.  This sporadic activity is about 7 meteors
per hour visible to the unaided eye.  This activity is comprised partly of
random meteors and partly of meteors that belong to long-ago, now
untraceable showers.

If you want to do some more reading on minor showers that are not on the
'Working List of Visual Meteor Showers' of the IMO, then check out Gary
Kronk's 'Comets and Meteor Showers' website at http://comets.amsmeteors.org
Most minor showers are really only detected by plotting your meteors on star
charts, and doing an analysis
after your observing session is over.  Special maps are available for
plotting with a gnomonic projection which allows you to plot your meteors as
straight lines.  The plotting maps generally in use are from the Atlas Brno,
and are available free of charge from Mr. Robert Lunsford, IMO
Secretary-General, at 161 Vance Street, Chula Vista, California 91910, USA.

In July, the moon phases are as follows:

Tues. July 02  last quarter
Wed. July 10  new moon
Wed. July 17  first quarter
Wed. July 24  full moon

The magnitudes of the planets in July (at midmonth unless stated) are:

Mercury  -0.3  low in east before sunrise, in first week of July
Venus     -4.1   low in west after sunset
Saturn      0.1   low in east before sunrise, in late July


3.  Summer Reading for Meteor Enthusiasts...

Summer is a great time for sunshine, cottages, and time at the beach!  And,
even if you're not into sun, sand and daylight... it is a great time to get
some good reading in!

There are some good books out there right now, and some are just ideal for
meteor fans.  This Canadian co-author recently spent a half day relaxing at
the local garage, waiting for truck repairs... and reading a novel by one of
the astronomers at the Armagh Observatory!  It's called "Nemesis", and is
written by Dr. Bill Napier, an authority on impact hazards.  It's about an
asteroid that has been deflected onto a collision course with the United
States, and how everybody deals with it.  I haven't finished the book yet...
my truck (only) needed front end work... but I would highly recommend the
novel.  Being written by a professional astronomer, it has lots of wonderful
astronomical information throughout.  The author also includes many witty
comments on a variety of life's circumstances, which really make you
smile...

On a non-fiction note, a good recent book is "Meteorites - Their Impact on
Science and History", originally published in French as "Les Meteorites".
It's a collection of very interesting articles by various authors on
impacts, meteorites, and meteoroid origins.  It is edited by Brigitte Zanda
and Monica Rotaru, and put out by Cambridge University Press.  There are
lots of photos, and excellent charts and diagrams to explain concepts.  The
book is easily readable by amateur astronomers.

So... if you are being dragged off to a cottage, and are wondering what book
to take along... grab one of these at your local bookstore.  Both will
entertain you!


4. Upcoming Meetings...

July 21-26, 2002, Los Angeles, California USA...
The 65th annual meeting of the Meteoritical Society will be held at the
University of California in Los Angeles. Special sessions planned include
'Mars: Meteorites and Missions' and 'Chondrule and CAI origins'. For
information, check out www.lpi.usradot edu/meetings/metsoc2002

July 29-August 2, 2002, Berlin, Germany...
The Asteroids, Comets, Meteors 2002 Conference will be held in Berlin,
Germany. Topics that will be covered include comets, asteroids, meteor
showers, interplanetary material, collisions and impacts, NEO's (near earth
objects), the asteroid-meteorite connection, transitional objects, origin of
comets, and many other related topics. This is the 8th ACM conference in a
series, with a conference being held only every 3 years. It is being jointly
organized by the DLR Institute of Space Sensor Technology and Planetary
Exploration, the Max Planck Institute for Aeronomy, and the Technical
University of Berlin.  For details, contact J. Benkhoff at acm2002@dlrdot de
and check out the ACM 2002 website at http://berlinadmin.dlrdot de/SGF/acm2002

September 3-6, Washington, DC, USA...
The Workshop on Scientific Requirements for Mitigation of Hazardous Comets
and Asteroids, sponsored by NASA, will be held in Washington, DC.  The
workshop will review current knowledge of the physics and chemistry of the
interiors of small cometary nuclei and asteroids, and will work towards
several goals:  determination of requirements for collision avoidance and
impact mitigation technologies, determination of mission models and
instrumentation needed, and construction of a roadmap for achieving the
knowledge on which to base future systems to deal with possible impacts.
Registration is $250 on or before July 1, and $350 after July 1.  A list of
the confirmed invited speakers can be found at
http://www.noaodot edu/meetings/mitigation/invited.html.  For information,
contact Nalin Samarasinha at nalin@noaodot edu and check out the conference
website at http://www.noaodot edu/meetings/mitigation.

September 26-29, 2002, Frombork, Poland...
IMC 2002, the International Meteor Conference, will be held in Frombork,
Poland. This is the annual conference of the International Meteor
Organization and welcomes all meteor observers, both amateur and
professional. For information, check out http://www.imodot net and
http://www.astrouwdot edu.pl/~olech/pkim/imc2002/imc.html. For specific
questions, contact Mariusz Wisniewski at pkim@astrouwdot edu.pl

For more information on upcoming astronomy meetings, see: "International
Astronomy Meetings List" http://cadcwww.hia.nrcdot ca/meetings


5. For more info...

NAMN email: namn@atmob.org
NAMN website: http://www.namnmeteors.org

Mark Davis, meteors@comcastdot net
Goose Creek, South Carolina, USA
Coordinator, North American Meteor Network

Cathy Hall, chall@cyberusdot ca
Metcalfe, Ontario, Canada
Co-author, NAMN Notes

Lew Gramer, dedalus@alum.mitdot edu
Medford, Massachusetts, USA
Coordinator, Public Outreach
Owner/Moderator, 'MeteorObs'

Kevin Kilkenny, Mail4Meteors@aol.com
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.mitdot edu

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

July 2002 NAMN Notes co-written
by Mark Davis and Cathy Hall
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