(meteorobs) NAMN Notes: December 2004

[Mark Davis]

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NAMN Notes:  December 2004
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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.  Geminids - The Best for Last!...
2.  Ursids, the Christmas Shower...
3.  Other December Activity...
4.  Comets, Aurora and More...
5.  Upcoming Meetings...
6.  For more info...


1.  Geminids - The Best for Last!...

For many meteor observers, the Geminids are the highlight of the year!  The
Geminids (GEM) reach a peak on December 13th this year, and can be seen from
about December 7th to 17th.  The IMO, the International Meteor Organization,
lists their ZHR as 120 meteors per hour - the highest on their list.

What is ZHR?  ZHR stands for Zenithal Hourly Rate, and is the number of
meteors that an observer could expect to see, on the average, in an hour of
observing.  This is observing with the unaided eye - but the rate is for
dark country skies, and with the radiant, the area in the sky where the
meteors seem to come from, directly overhead (at the zenith).

How do the Geminids stack up to this in December?  New moon is on December
12th - so the sky will be nice and dark, as long as you get out into the
country, and away from the light pollution of the city.  Gemini is
visible all night - and rates will increase as it gets higher in the sky.

The parent body of the Geminids is the asteroid 3200 Phaethon.  This was
announced by the International Astronomical Union (IAU) in 1983, and was the
first time that an asteroid, as opposed to a comet, had been linked to a
meteor shower.  Some investigators say that Phaethon is the largest remnant
of the parent of the Geminid stream, and that it is still unclear as to what
the true 'parent' is.  The IMO states that "the first indications of the
Geminid meteor shower were published by the early Belgian meteor researcher
Quetelet (1841, 1861), who mentioned high meteor activity on 1830 December
12-13 at Heiligenstadt (Germany), from where 40 fireballs were reported".

On December 13th, the maximum activity will be at about 22h 20m UT +/- 2.3h,
according to the IMO.  For North American observers, this means about 5.20
p.m. EST, plus or minus 2.3 hours.  At maximum, the radiant will be at 112
degrees, ie. RA 07h 28.2m, Dec +33, which is close to the bright star Castor
in Gemini.  A map showing the radiant can be found at
http://www.imo.net/calendar/cal04.html#Geminids

Geminids are average velocity meteors, at about 35 km per second - and many
are bright!  Because they are not fast, it is easier to pick them up with
the eye - and also on photographs, if you wish to try.

For photographs, you will need a camera with a time exposure setting, in
order to leave the lens open for a number of minutes.  Under a dark sky,
with fast film, you can easily do 10 to 20 minute exposures.  Digital is
great - but if your digital camera won't do time exposures, use your old
reliable film camera!  Set the lens wide open, and the focus at infinity.
You will need a cable release to keep the lens open.  Use a normal or wide
angle lens as meteors are long, and you don't want to restrict your field of
view.  Use a tripod if you have one - if not, put your camera on a flat
surface, with a towel or mitten underneath to keep it from moving.  As
meteors will be seen all over the sky, you don't need to face (or point your
camera) at the constellation of Gemini in order to see Geminids.

If you want to record data on the Geminids 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.  For estimating the brightness of the meteors you see, we have a
handy set of 4 star charts (set printer to 'landscape mode') at
http://www.namnmeteors.org/charts.html.  If you have any questions, drop a
note to our NAMN Coordinator at meteors at comcast.net

Forms to record your observations can be found at
http://www.namnmeteors.org/namn_form.html and
http://www.namnmeteors.org/appendixC.html.

Dress warm.  The Geminids, besides being favored with long nights to
observe, also bring cold temperatures as well.  Dress in layers.  Wool and
polar fleece fabrics are good.  By layering clothes, you trap air, which is
a good insulator.  Use a reclining chair so you can stretch out and be
comfortable.  Put an insulating mat or extra blanket underneath your
sleeping bag - as the cold will get at you from underneath as well.  A
recommended guideline is to pretend that it will be twice as cold as it
really is - that way, you should be dressed just warmly enough!  Don't
forget it is very important to cover your head properly too, or you will
lose heat rapidly.  A hat and scarf should be used, to cover as much of your
head and face as possible.  A balaclava - a covering with holes for eyes,
nose and mouth - will keep you much warmer.  Take extra blankets.

For recording your meteors, you can use paper and pencil for your data, or
if you have access to one, a small tape recorder is very useful.  If you use
a tape recorder, keep it warm so the batteries don't die in the cold.
Always take paper and pencil as backup.  Set your watch to accurate time
before you go out observing.  A talking watch (available through
institutions for the blind) is useful, but again, keep it warm or the
battery will cease to function.  A red flashlight is a necessity - cover
your flashlight with something red so the light does not destroy your dark
adaptation to the skies.  Take extra batteries, and keep them in a warm
place.

The International Meteor Organization, in their 2004 Meteor Shower Calendar,
sums up the Geminids:

"One of the finest annual showers presently observable...  Well north of the
equator, the radiant rises around sunset, and is at a usable elevation from
the local evening hours onwards.  In the southern hemisphere, the radiant
appears only around local midnight or so.  Even here, this is a splendid
shower of often bright, medium-speed meteors, a rewarding sight for all
watchers."


2.  Ursids, the Christmas Shower...

The Ursids (URS) are a little-observed shower as they occur at one of the
busiest times of the year, just before Christmas.  However, it would be very
valuable to obtain more information on this shower!

The Ursids start about December 17th, and run until about December 26th.
The maximum this year is on December 22nd.  According to the IMO, the peak
is "most likely near 7h UT, but possibly up to two hours or so later".  For
North American observers, this means about 2.00 a.m. on Wednesday December
22nd, or possibly 2 hours later.

These are average velocity meteors, at about 33 km per second.  They tend to
be faint.  ZHR rates are about 10 meteors per hour at the peak.  On
occasion, this shower has surged up to about 50 meteors per hour, so it is
worth monitoring!

The Ursids bear an association with Comet Mechain, now called Comet Tuttle.
Pierre Mechain of France discovered the comet on January 9, 1790, but there
were not enough observations of it to discover its periodic nature.  It was
recovered on January 5, 1858 by Horace Tuttle of Massachusetts, and given
his name instead.

The radiant of the Ursids at their peak is at 217 degrees, ie. RA 14h 28.2m,
Dec +76, which is just above the pointer stars of Ursa Minor, the Little
Dipper.  For a map showing the radiant, check out
http://www.imo.net/calendar/cal03.html#Ursids

Do something different this Christmas - get out and observe this little gem
of a shower.  As Lew Gramer, our MeteorObs discussion group moderator, often
reminds us:  You could be the only person on the planet observing on that
night - your observations are very valuable!


3.  Other December Activity...

We have lots of other meteor shower activity in December!  If you haven't
already done so, print off a set of our 4 NAMN star charts.  They are found
at http://www.namnmeteors.org/charts.html.  They have lots of 'standard'
stars marked, to use in estimating the brightness of the meteors you see -
and they have both types of coordinate systems labelled, so you can easily
mark your meteor shower radiants on them before heading out observing.

The chi Orionids (XOR) reach a maximum on December 1st, and last until about
December 15th.  These are almost slow meteors, with a velocity of about 28
km per second.  ZHR rates at maximum are about 3 meteors per hour.  These
meteors are considered to be possibly a continuation of the ecliptic
activity after the Taurids are no longer active.  There are occasional
fireballs as well.  A map showing the radiant can be found at
http://www.imo.net/calendar/cal02.html#chi-Orionids

The Phoenicids (PHO), although a more southerly shower, merit note.  They
started to become active about November 28th, and peak on December 6th at 2h
35m UT (ie. 9.35 p.m. EST on December 5th).  They last until about December
9th.  They are quite slow, with a velocity of about 18 km per second.  ZHR
rates are variable - usually 3 or fewer meteors per hour, but did reach
about 100 meteors per hour back in 1956.  A map of the radiant can be found
at http://www.imo.net/calendar/cal04.html#Phoenicids

The Puppid-Velids (PUP) are a southern shower lasting from about December
1st to 15th, with a maximum about December 6th.  These are average velocity
meteors, at about 40 km per second.  ZHR rates are about 10 meteors per hour
at maximum.  According to the IMO, "this is a very complex system of
poorly-studied showers, visible chiefly to those south of the equator.  Up
to ten substreams have been identified, with radiants so tightly clustered,
visual observing cannot readily separate them.  Photographic, video or
telescopic work would thus be sensible, or very careful visual plotting...
Most Puppid-Velid meteors are quite faint, but occasional bright fireballs,
notably around the suggested maximum here,  have been reported".  The
radiant at maximum is at 123 degrees, ie. RA 08h 12m, Dec -45, which is
about 17 degrees down to the left of the star eta Canis Major.

The Monocerotids (MON) started about November 27th, peak on December 8th,
and can be seen until about the 17th.  Telescopic results suggest a peak
perhaps around December 16th.  These are average velocity meteors, at about
42 km per second.  ZHR rates are about 3 meteors per hour at maximum.  The
meteors are usually faint.  According to recent studies, this shower could
be the source of many of the spectacular fireballs of the eleventh century.
Many of these are documented in the writings of Ma Touan-lin, a historian of
the pre-Mongolian era, who collected observations of over 1,500 fireballs
going back over 24 centuries!  For a map showing the radiant movement of
this shower, check out http://www.imo.net/calendar/cal04.html#Geminids

The sigma Hydrids (HYD) can be seen from about December 3rd to 15th, and
reach a maximum on December 11th.  However - recent data suggests the peak
may occur up to 6 days earlier.  These are fast meteors, at about 58 km per
second.  They are usually faint.  ZHR rates are about 2 meteors per hour at
the maximum.  A map of the radiant can be found at
http://www.imo.net/calendar/cal04.html#sigma-Hydrids

The Coma Berenicids (COM) can be observed from about December 12th to
January 23rd, and reach a peak on December 19th.  These are fast meteors, at
about 65 km per second.  At the peak, the ZHR rates are about 5 meteors per
hour.  This shower is possibly associated with Comet Lowe, 1913 I,
discovered by an amateur astronomer in south Australia.  A map showing the
radiant is at http://www.imo.net/calendar/cal04.html#Coma-Berenicids

Besides December's main activity, and other minor showers, there is also
sporadic meteor activity - about 7 meteors per hour, visible to the unaided
eye.  Some of these are random, and some belong to old untraceable meteor
showers.

Planets at midmonth, and their magnitudes, for northern observers, are:
Venus      -4.0   low in southeast in morning twilight
Jupiter    -1.9   in Virgo, in east in morning sky
Saturn     -0.1   in Gemini
Mars        1.7   in Libra, low in southeast in morning sky

On December 5th, Venus will be 1.3 degrees north of Mars.  On December 7th,
Jupiter will be 0.3 degrees south of the moon, with an occultation visible
from central and eastern North America, northeast Brazil, and western and
central Africa.

This month, the phases of the moon are as follows:
Sun. Dec.  5    last quarter
Sun. Dec. 12    new moon
Sat. Dec. 18    first quarter
Sun. Dec. 26    full moon
For a great printout of moon phases for the month, check out
http://stardate.org/nightsky/moon


4.  Comets, Aurora and More...

Just a reminder to all observers to stay alert for comets, aurora and other
interesting things in our skies in December as well!

Wondering what constellations you will see tonight?
Go to Heavens Above.  Just click Select, then your country, then your city,
and go to Whole Sky Chart.  Pick a time of night, then choose 'black on
white' to print a great map of the whole sky.  It shows all the planets too.
http://www.heavens-above.com

Wondering if there are northern lights visible tonight?
Go to SpaceWeather.  It tells when and where aurora is happening - and shows
all the photos afterwards.  We recently had aurora visible as far south as
Arizona - so don't think you have to live up north to see northern lights!
http://www.spaceweather.com

Wondering what satellites you can see tonight?
Go to Heavens Above.  ISS, the International Space Station is a favorite.
There are hundreds of other satellites - and Heavens Above tells you what
they are, when to look, and has star charts to show you where to find them.
http://www.heavens-above.com

Wondering what comets are visible tonight?
Go to Seiichi Yoshida's 'Weekly Information about Bright Comets'.  Comets
are listed in order by brightness, so even if you have a modest-sized
amateur telescope, this site is really wonderful!
http://www.aerith.net/comet/weekly/current.html

Ok, how do you get coordinates for a particular comet?
Go to the IAU CBAT site.  That's the International Astronomical Union's
Central Bureau for Astronomical Telegrams.  They have a page giving daily
coordinates for comets.  Make note of the official comet name from
Yoshida's site first, then pick the comet, and go to 'daily ephemeris'.
http://cfa-www.harvard.edu/iau/Ephemerides/Comets/index.html

Ok, give me an easy printable finder chart for the comet I want to see!
Go to Greg Crinklaw's 'Skyhound'.  He has finder charts for all the
brightest comets, and details of visibility from different latitudes.
http://www.skyhound.com/sh/skyhound.html

One of the brightest comets will be C/2004 Q2 Machholz, discovered by comet
hunter Don Machholz of the southwestern United States on August 27th, using
his 6 inch f/8 telescope.  This is Machholz's 10th comet discovery, after
7,046 hours logged since January 1, 1975.  A finder chart for Comet Machholz
can be found at http://www.skyhound.com/sh/skyhound.html


5.  Upcoming Meetings...

August 7-12, 2005, Brazil...
ACM 2005, the IAU Symposium 229:  Asteroids, Comets, Meteors, will be held
in Rio de Janeiro, Brazil.  The main topics of the conference will be space
missions, internal structure of asteroids and comets, connections between
asteroids, cometary nuclei and Trans-Neptunian Objects (TNO's), connections
between asteroids and meteorites, connections between comets, meteor showers
and interplanetary dust, minor body dynamics, collisions and impacts,
Near-Earth Objects (NEO's), origin and evolution of our Solar System and
extra-solar planetary systems.  The website for the conference is at
http://www.on.br/acm2005.  For more information, contact Daniela Lazzaro or
Fernando Roig at acm2005 at on.br

September 15-18, 2005, Belgium...
The 2005 IMC, International Meteor Conference of the IMO, the International
Meteor Organization, will be held in Oostmalle, Belgium.  Oostmalle is about
70 km north of Brussels, and about 30 km northeast of Antwerp.  The
conference is being organized by Urania, the public observatory of Antwerp.
Accommodation will be at the Provinciaal Vormingscentrum Malle, with an
excursion to the city of Lier.  This is a great opportunity to meet and
chat with meteor observers from all around the globe - so mark it on your
calendar now, and plan to attend!  The participation fee is 120 EUR, and
includes all accommodation, all meals, and the conference registration.  For
information, check out the conference website at http://www.imo.net/imc2005.
For questions, contact Jan Verbert at imc2005 at imo.net

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


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
Metcalfe, Ontario, Canada
Writer, NAMN Notes

Lew Gramer, dedalus at alum.mit.edu
Medford, Massachusetts, 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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'Clear Skies' for December
Merry Christmas to all...
December 2004 NAMN Notes
>From Davis and Hall... :)
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