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(meteorobs) NAMN Notes: November 2002
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NAMN Notes: November 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. Leonids - Your Planning Guide...
2. Alpha Monocerotids...
3. Other November Showers...
4. Upcoming Meetings...
5. For more info...
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1. Leonids - Your Planning Guide...
The Leonids are the main meteor event of 2002. Much has been written about
them in the current issues of the astronomy magazines in North America, and
there are many good articles and online links.
The Leonids are an incredible meteor shower - take a look at some of the
best images from last year's display over Japan, by Shigemi Numazawa:
http://www1.nisiqdot net/~numazawa/nippou/leo01e.html
The November 2002 Leonids are very special as they may well be the last
chance for us to see a real meteor 'storm' in our lifetime! Mark November
18th and 19th on your calendars now!
Perhaps the best single website for the Leonids this year is that of Dr.
Peter Jenniskens and the Leonid MAC team at http://leonid.arc.nasadot gov. The
site provides a wealth of information on the Leonid meteor shower, its
parent comet, and the researchers and experiments flying on the NASA
airborne scientific mission.
A very interesting graphical representation of predicted rates by the main
research teams can be found on the website of Hiroshi Ogawa, of the
University of Tsukuba, Japan. He plots meteor rates on world maps, using
colored grid lines for easy reference. A definite site to check out!
http://homepage2.nifty.com/~baron/leo02forcast.htm
What do you really need to know about the predicted Leonid meteor storm in
November? Let us fill you in!
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i) The shower - what is it about?
The Leonids (LEO) are debris from Comet Tempel-Tuttle. The earth will
intersect the path of this debris from November 14th until the 21st, with a
special concentration of debris hitting the earth's upper atmosphere around
November 18th and 19th. Leonids occur every year when the earth passes
through old comet debris.
So, what makes this year special? The rates are predicted to be much higher
than normal this year, in fact to hit 'storm' level of at least several
thousand meteors per hour, for several short durations of time! This
activity is in addition to the much lower general Leonid meteor rates over
the period November 14th to 21st.
The radiant, the area in the sky where the meteors will seem to come from,
is at 153 degrees, ie. RA 10h 12m, Dec +22, which is up in the 'sickle'
of the constellation of Leo. These are extremely fast meteors, with a
velocity of about 71 km per second. You can see a map of the radiant on the
website of the International Meteor Organization (IMO) at
http://www.imodot net/calendar/cal02.html#Leonids as well as a link to the
IMO's special 2002 Leonids page.
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ii) How many meteors will we really see, and when?
Predictions vary, depending on the researcher, the assumptions and methods
used in the analysis, and the data analyzed.
Every 33.2 years, the parent comet passes around the sun in its orbit, and
sheds debris. This debris takes on a slightly different orbit from the
parent comet - and the debris shed in each subsequent comet return is laid
down in a slightly different orbit. Over the years, we end up with a
number of filaments or trails of debris, each in slightly offset orbits.
When the earth passes through this area in space, it passes through a number
of different trails at different times.
The researchers call each trail by the number of revolutions around its
orbit that the dust has made since being shed. Some trails will produce
more meteors than others. Some will have less debris in them and be almost
insignificant - and the researchers may not quote meteor rates expected from
those. The trails that are quoted in predictions this year are the 4-rev
trail (debris from 1866), the 5-rev trail (debris from 1833), the 6-rev
trail (debris from 1799) and the 7-rev trail (debris from 1767). The trails
expected to produce the most meteors are the 4-rev trail and the 7-rev
trail.
The meteor rates per hour are quoted as a Zenithal Hourly Rate (ZHR). This
is
the number of meteors, on average, that an observer would expect to see
if they were 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. Keep in
mind that the peak of the Leonids falls on full moon this year - so the
fainter meteors will not be as visible and the actual rates seen by
observers will be lower than the quoted ZHR rate.
The time is quoted in Universal Time (UT) which is also the time at
Greenwich, England. For observers in North America on Eastern Standard
Time (EST), subtract 5 hours. For other time zones, adjust accordingly.
Note: Before we get into the storm predictions, note that there will
still be regular Leonid activity occurring. The time of the maximum for
the regular activity is listed by the IMO in their 2002 Meteor Shower
Calendar as November 17th at 20h UT, ie. for observers on Eastern Standard
Time (subtracting 5 hours) means 15h EST, which (subtracting 12) means 3
p.m. in the afternoon on November 17th. According to the IMO, "the November
17 timing favours places from Asia and Russia eastwards to the Far East and
Australia."
The available storm predictions that most observers are aware of, as at
the time of writing in late October, are the following. The storm
components will occur a day and a bit later than the regular activity
peak.
Note: When the duration of the trail peak is given, it is referring to
'full width half maximum' (FWHM), the period of time over which the rates
are
predicted to be at least half the maximum number of hourly meteors
predicted. Hence observers should make sure to start watching ahead of
time, and keep watching after the predicted time!
The team of Esko Lyytinen, Tom Van Flandern and Markku Nissenen predict (in
ZHR rates):
Nov. 19 04.03 UT (11.03 pm EST on Nov. 18) 7 rev trail 3500/hr
Nov. 19 06.36 UT (01.36 am EST on Nov. 19) 5 rev trail 160/hr
Nov. 19 10.40 UT (05.40 am EST on Nov. 19) 4 rev trail 2600/hr
This team also mentions that the "7 rev trail meteors are brighter, so they
are more easily seen in the sky brightened by the Moon" and that there may
be a "possible weak 7 rev trail sub-peak" slightly before the main 7 rev
trail peak. The 7 rev trail peak is predicted to last about 106 minutes,
and the 4 rev trail peak about 122 minutes. More details are available at
http://www.ursa.fi/ursa/jaostot/meteorit/leoeng02.html
Dr. Peter Jenniskens predicts (in ZHR rates):
Nov. 19 03.48 UT (10.48 pm EST on Nov. 18) 7 rev trail 5900/hr
Nov. 19 04.50 UT (11.50 pm EST on Nov. 18) 6 rev trail 51/hr
Nov. 19 05.59 UT (00.59 am EST on Nov. 19) 5 rev trail 28/hr
Nov. 19 10.23 UT (05.23 am EST on Nov. 19) 4 rev trail 5400/hr
According to Jenniskens, the 7-rev trail peak will last about .64 hours
(about 38 minutes), the 6-rev trail peak about 4.1 hours, the 5-rev trail
peak about 4.8 hours, and the 4-rev trail peak about .60 hours (about 36
minutes). More details are available at
http://leonid.arc.nasadot gov/1998.html and predictions covering many cities
around the world are posted at
http://science.nasadot gov/headlines/y2002/09oct_leonidsforecast.htm?list519943
The team of Jeremie Vaubaillon and Francois Colas predict (in ZHR rates):
Nov. 19 04.04 UT (11.04 pm EST on Nov. 18) 7 rev trail 3400/hr
with a range between 3100-3700/hr
Nov. 19 10.47 UT (05.47 am EST on Nov. 19) 4 rev trail 3000/hr
with a range between 2700-3300/hr
According to Vaubaillon and Colas, the 7-rev peak will last about 2 hours,
and the 4-rev peak about 3 hours, with a possible secondary peak. A basic
description of how this was computed is found on their (updated) website at
http://www.imcce.fr/s2p/leonides/predictions/Leonid_forecast.html
The team of Robert McNaught and David Asher predict (in ZHR rates),
according to the article published in WGN 30-5 of October 2002:
Nov. 19 03.56 UT (10.56 pm EST on Nov. 18) 7 rev trail 1000/hr
with a range between 810-2000/hr
Nov. 19 10.34 UT (05.34 am EST on Nov. 19) 4 rev trail 6000/hr
with a range between 2900-6000/hr
According to McNaught and Asher, the 7-rev trail peak will last about 130
minutes (with a possible range of 105-150 minutes), and the 4-rev about 71
minutes. In their article, they mention that "the 4-rev dust trail... has
had no close encounters with the Earth since it was formed... The situation
is very different for the 7-rev trail... Numerous disruptions are caused by
the Earth's passage close to the trail." They also comment on the
brightness of the meteors that will be seen: "Despite the probably higher
ZHR of the 4-rev trail in 2002, the lower <difference in semi-major axis
between the ejected particle and the comet at the time of ejection> of the
7-rev trail... will result in a higher proportion of bright meteors. This
will have a marked bearing on observed meteors for lower limiting magnitudes
as would be expected in full moonlight."
McNaught and Asher, in their conclusion to the article in WGN, comment:
"Some uncertainty in the peak ZHR exists for both these trails that could
increase the predictions by up to a factor of three. For the 7-rev trail
over European longitudes the uncertainty results from the high ZHR from the
same trail in 2001. Overall, it does not appear warranted to assume the
observed activity of the non-linear encounter in 2001 should automatically
imply higher than nominal rates in 2002, but without very extensive
calculations we cannot deny this possibility. The 4-rev trail over N.
American longitudes falls in roughly the same ZHR parameter space as the
1833 and 1966 Leonid storms. Given that both these storms seem rather
underpredicted by our ZHR model, and bearing in mind that these are the only
two linear encounters that are so badly predicted, it seems reasonable that
the 4-rev encounter in 2002 could be double the nominal ZHR prediction."
So, how many meteors will we really see? It will be up to observers all
around the globe to gather observations to find out! According to the
researchers, in spite of all their efforts, we could still be in for some
surprises. The International Meteor Organization, in their 2002 Meteor
Shower Calendar, emphasizes that "other unexpected peaks are not excluded,
so all observers should be alert right over the probable maximum dates, from
November 16-20 especially."
As Jeremie Vaubaillon phrased it so well on the MeteorObs email list on
September 10th:
"I think the important thing is to consider that, on next Nov. 19th, there
will be a very strong Leonid shower, and perhaps the last you can see in
your whole life (so strong I mean). So just remember to observe!"
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iii) Where do we have to go to see the Leonids?
There are a number of factors to take into account when it comes to deciding
on a location.
First, take a look at these peak times on the night of the 18th and morning
of the 19th. Is the Leonid radiant above your horizon at those times?
Maybe not. If not, you won't see many of those meteors.
When the radiant is just below your horizon, or just above, you will see
'earthgrazers' - nice long Leonids coming up from the horizon. In a posting
to the MeteorObs email list on September 16th, meteor researcher Pete Gural
wrote "... using a meteor simulation analysis one can show that to observe
grazers that reach above 30 degrees elevation, the radiant must be between 2
degrees below the horizon to 3 degrees above the horizon... for northern
latitudes the duration is roughly one-half hour but at the equator this can
last for up to 40 minutes."
If you have a sky program on your computer, dial up November 18th and 19th,
and see when the sickle of Leo rises over your local horizon. You can also
check out what time the sickle of Leo will rise by adjusting the date and
your local time on the 'Whole Sky Chart' on the Heavens Above website, at
http://www.heavens-above.com
Basically, observers in Europe will see the first big peak well, and
observers in the Americas may see nice long 'earthgrazer' meteors from that
peak, around 11.00 pm EST on November 18th. The second big peak will favor
the Americas, around 5.30 am EST on the morning of November 19th.
What hours do you have in darkness from the location where you live? What
time does twilight end and start? Check these times against the predicted
peak times for the various rev trails. You might want to travel to get more
hours of darkness centered on the time of maximum activity! This can be
especially crucial if the peak time is shifted a bit from predictions. You
might want to give yourself a bit more 'time zone safety'. Get your
times of twilight from the U.S. Naval Observatory site at
http://aa.usno.navy.mil/data/docs/RS_OneDay.html
Apart from radiant height and hours of darkness, what factors should we
consider for location?
Cloud cover. If you live in an area that is always cloudy and/or rainy or
snowy in November, get out. Go somewhere that has a higher percentage of
clear skies in mid-November. To see a global map of mean November cloud
cover at night (from 18 years of satellite data), check out Jay Anderson's
site at http://home.cc.umanitobadot ca/~jander/Leonids/leonids.htm
Elevation. November can bring heavy fog when the temperature drops at
night. Get as high as you can above ground level. Check out your
topographical maps, or take a look at some online relief maps.
For the U.S., check out the U.S. Color Landform Atlas at:
http://fermi.jhuapldot edu/states/states.html.
For Canada, check out the following address for a great interactive zoom-in
relief map: http://www.geoaccessdot ca/site/english/maps/reference/national/
then choose Reference Maps - National - Relief (Interactive).
Humidity. Humid air - and not just ground fog - may also hamper
observations this year. Because there will be a full moon, the humidity in
the air will tend to dissipate the light, and make your viewing more washed
out. If you can, try to get to a dryer area to observe.
Aurora. No, we're not kidding. Those of us in northern latitudes have been
fortunate to see a lot of aurora lately. However spectacular these may be,
we don't want a bright aurora with a full moon as well on the Leonid
maximum. Watch the aurora site at http://www.spacew.com/www/aurora.html to
see if you should consider traveling further south.
Those are the main location factors. Temperature is secondary - but
November is winter, and if you can't take the cold, go south to observe if
you can afford it.
Stay mobile - be prepared to relocate at the last moment if you need to
escape cloud, fog or other factors that may impede your view of the Leonid
meteor storm. Consider mobility now. Check out friends or astronomy
contacts in various locations, to give you some observers to hook up with if
headed to a strange location. Make a list now of contacts and observing
locations - say 4-5 hours north, south, east, and west of you in driving
time - and another list say a 9-10 hour drive in each direction. Pack your
car and be prepared to move. Get your identification and customs slips
ready to go in case you have to cross a border. A good list of astronomy
clubs can be found on the Sky and Telescope website at
http://skyandtelescope.com/resources/organizations/
If you cannot travel, and just want to link up with a group of local
observers and take your chances on the weather, this Sky and Telescope link
will also give you details on the club closest to you!
In spite of the full moon brightening the sky though, it is still very
important to try to get out of the city. Bright glaring streetlights will
blind you to many of the meteors falling in the sky! Man-made light
pollution still destroys our night sky.
Bookmark the following weather websites for reference, and watch them
carefully in the days leading up to the Leonids:
Maps of where clear skies are now, and in 24 hours time, in North America:
http://www.cmc.ec.gcdot ca/cmc/htmls/clds_vis_e.html and also
http://www.intellicast.com - choose Stargaze, then Viewing Conditions.
Map of the predicted travel weather in 1/2/3/4/5 days time:
http://www.intellicast.com and choose Travel.
Also check out Canadian observer Attilla Danko's 'Clear Sky Clocks' for
astronomical viewing conditions at locations across North America. You can
pick a location, check it out, then ask to see conditions at sites within 60
miles, or 120 miles - an extremely useful tool!
http://www.cleardarksky.com/csk/
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iv) What equipment do we need for observing?
This is an open question, and depends to a large degree on the type of
observing you wish to do.
A basic checklist for casual sky watchers would include the following:
- campcot or reclining lawnchair
- foam mat to put on chair
- sleeping bag to put on mat
- a spare blanket
- a pillow (yes, use a pillow, it helps keep you comfortable!)
- waterproof tarp to put over sleeping bag to keep off dew and frost
- star charts, printable from our NAMN site at:
http://www.namnmeteors.org/charts.html
- a red flashlight to read your charts
- paper, pencils and clipboard to record any notes you take
- some hand warmers, either the lightable stick kind (take matches or
lighter), or the disposable pouch kind
- thermos of coffee, and a snack (but be cautious if animals around)
- warm coat, hat, mittens, scarf to keep nose and neck warm
- if down south - appropriate attire and insect repellant
- small pair of binoculars to watch meteor trains with
- last, but very important - a dark colored umbrella to help block the full
moon from your view! (an appropriately placed mountain or tree would
suffice as well)
If you are actually going to record the meteors you see, then add the
following:
- (preferably) a pocket tape recorder, with spare tapes and batteries
- extra batteries (they die easily in the cold)
- recording sheets for your meteors, printable from:
http://www.namnmeteors.org/namn_form.html
- extra paper in case of a recording emergency!
- star charts showing limiting magnitude areas, printable from:
http://www.imodot net/visual/major01.html#table2
- a watch or clock set to accurate time (a talking watch or clock is
preferable so that you do not need to take your eyes off the sky
to check the time)
- extra warm clothes - extra layers, extra mittens
- a couple more blankets (no kidding!)
If you want to photograph some Leonids, then add:
- a camera that has a time exposure setting
(a simple digital camera or instacam won't work for this)
- a normal lens, or a wide angle lens (fast f/ratio preferable)
- cable release
- fast film - either print or slide, either color or black and white
- extra film
- tripod
- lens hood
- heat source to keep lens dry (disposable hand warmer pouch can be used
with elastic)
- if not a manual camera, lots of extra batteries for the cold
If you want to try videotaping some Leonids, add:
- video camera
- extra video tapes
- extra battery packs
- and still more battery packs!
If you are traveling to see the Leonids, do and pack the following:
- put your snow tires on before the trip
- add weight to your trunk if rear wheel drive
- get a tuneup for your car
- identification if crossing borders
- customs slips for all your cameras, lens, tripods, etc.
- a safety flashlight with fresh batteries
- jumper cables
- a fire extinguisher
- emergency blankets and full first aid kit
- spare oil, antifreeze, and premixed radiator fluid
- a shovel and a bag of sand or kitty litter (it's winter!)
- cell phone if possible
- phone numbers of all your contacts!!
- road maps of the provinces/states you will visit
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v) For recording meteors, what should we record?
For information on what to record for visual observing, check out our NAMN
Observing Guide at: http://www.namnmeteors.org/guide.html
This gives the basic info on what visual data we usually record for each
meteor - time of occurrence, brightness (magnitude), shower it belonged to,
speed of meteor, how long the trail lasted if it had one, and any color or
unusual characteristics.
While rates are low, before and after the peaks on November 18/19, and
on the nights leading up to and after November 18/19, an observer can either
use a tape recorder or a paper roll or recording sheets to write their
meteor data on. Recording sheets can be printed off from
http://www.namnmeteors.org/namn_form.html
When the Leonid rates start to really pick up, all of this info will not be
possible to record on tape, or on a written paper roll, for each meteor.
Most of us will then revert to just times and magnitudes of Leonids - and
not record meteors from minor showers. If rates get even higher, then an
observer will have to devise their own recording strategy. Some observers
in the past have resorted to just calling 'beep' onto their tape under these
sorts of conditions. Make sure you continue to put time markers on your
tape though - preferably every minute in periods of enhanced activity. A
talking watch or clock (available at supplies for the blind) makes this much
easier.
If the rates get so high that you cannot count, be prepared to switch to
your camera to record them! For photographic observations, record the start
and stop times for each exposure, and details on film, camera lens and
f/stop used. Basically, fast film and fast lenses are good, but exposures
may have to be shortened to a handful of minutes to counteract the full moon
sky conditions. For beginners, or those trying astrophotography for the
very first time, read the excellent articles by Dennis di Cicco at
http://skyandtelescope.com/howto/imaging/article_159_1.asp and by Pierre
Martin at http://www.oaogdot ca/Meteors/IntroPhoto.htm Instructions for
serious meteor photographers can be found on the IMO website at
http://www.imodot net/photo/index.html
For video observations, again, record the start and stop times for your
exposures, and details on your video camera settings. Information on
special meteor video techniques can be found on the IMO website at
http://www.imodot net/video/index.html A suggestion was posted to our
MeteorObs email list on October 14th by Rob McNaught: "It would be nice to
have some standardization in video observations to help analyze activity.
Pointing the camera at the celestial pole (Polaris for northern observers)
will give a constant radiant elongation and Moon elongation throughout the
night and for most observers, a camera elevation of ~45 +/- 10 deg...
arbitrarily placing cameras over the sky must complicate analysis."
For those technical (perhaps deep sky) observers wanting to use their CCD
equipment to capture meteor activity, check out the CCD's and
Astrophotography page at http://pages.sprintdot ca/todd/files/ccd.html for
links which may prove useful. You will find helpful information in the IMO
links as well at http://www.imodot net/video/index.html
(However - and this is important - never be intimidated by instructions! If
you do not have the equipment recommended by the experts for photography or
video work - try anyway! You don't always have to use the 'recommended'
types of film. You don't always have to have the 'recommended' camera. You
may be into photography for the joy of photography. Experiment and enjoy
yourself while watching your Leonids!)
In all cases, and especially if you travel, get a reading on your location's
latitude and longitude. Note your weather conditions. Note what percentage
of your sky is obscured by buildings or trees. Note your limiting
magnitude - how faint is the faintest star you can see? Check out the
charts available for judging limiting magnitude at
http://www.imodot net/visual/major01.html#table2 and print yourself off a set
if you are serious about your observations.
There is a meteor 'storm' simulation on the website of the IMO, the
International Meteor Organization. It was written by Sirko Molau, the IMO
Video Commission Director. Check it out at http://www.imodot net/ under
Software. It is called MetSim. It is good practice for estimating just how
well you would be able to judge really high meteor rates!
In all cases, record all the data you can. We need as much coverage around
the globe as we can get. If you have questions, drop an email to our NAMN
Coordinator at meteors@comcastdot net
After the peak is all over, and you are doing up your visual report, an
email template to use in typing out your observations is available at
http://www.namnmeteors.org/appendixC.html Then email off your report to our
NAMN Coordinator at meteors@comcastdot net. Photographic and video reports can
be sent to NAMN, and we will also forward them on to the International
Meteor Organization for you.
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vi) Where can we get more specialized information?
Check out the links on Lew Gramer's 'MeteorObs' website at:
http://www.meteorobs.org/storms.html
For more information on visual meteor observing, check out:
http://www.imodot net/visual/major01.html
For those after more photographic information, check out:
http://www.imodot net/photo/handbook/summary.pdf
For those radio buffs interested in trying some meteor recording by radio
means, check out Shelby Ennis' website "High Speed Meteor Scatter and
JT44 EME" at http://www.qsldot net/w8wn/hscw/hscw.html. Click on the
"Hot News" icon for details on Leonids by radio. Even if you're not into
the radio hobby, check out the cool graphics! Also, check out the IMO radio
info at http://www.imodot net/radio/index.html Links to other radio meteor
sites can be found at http://www.imodot net/radio/other_sites.html. Details on
the International Project for Radio Meteor Observation can be found at
http://homepage2.nifty.com/~baron/leo02p.htm
An excellent book for reading about the Leonids is 'The Heavens on Fire:
The Great Leonid Meteor Storms' by Mark Littmann, published by Cambridge
University Press.
An interesting paper on the history of the Leonids that can be printed off
from the web is 'The Leonid Meteor Shower: Historical Visual Observations'
by Peter Brown, available at:
http://www.astro.uwodot ca/~pbrown/documents/1999-Leonids-Icarus.pdf
Extensive historical information on the Leonids can also be found on Gary
Kronk's excellent website 'Comets and Meteor Showers' at
http://comets.amsmeteors.org
And - most importantly, stay tuned to our MeteorObs email list! Some of you
will be receiving this newsletter by independent email. MeteorObs is an
email meteor discussion list frequented by observers all around the globe.
Around Leonid time it will provide many valuable answers to all your
questions. To sign up - even if you just want to listen in during the
Leonids - fill in the online subscribe form on the MeteorObs website at
http://www.meteorobs.org/subscribe.html. You can unsubscribe at any time by
using the same form.
Clear skies to all... and good luck for the 2002 Leonid storm season!
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2. Alpha Monocerotids...
The alpha Monocerotids (AMO) reach a maximum on November 21st this year, at
about 20.30 UT, which is 15.30 EST, ie. 3.30 pm on the 21st. They can be
seen from about November 15th to 25th.
Like the Leonids, these are very fast meteors, at about 65 km per second.
At maximum, the radiant will be at 117 degrees, ie. RA 7h 48m, Dec +01. A
map showing the position of the radiant can be found at
http://www.imodot net/calendar/cal01.html#alpha-Monocerotids
These meteors have been known for the occasional outburst in the past!
Their rates are listed as variable by the IMO. The ZHR rate will probably
be about 5 meteors per hour, but has been known to hit 400 meteors or more
per hour! This occurred in 1995. This year, like the Leonids, they will
suffer from a very bright moon. However - get out and monitor this shower.
If they did exhibit unusually high rates this year, you would hate to miss
them just because you were too busy celebrating or commiserating after the
Leonids!
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3. Other November Showers...
There are other meteor showers active in November! If we have piqued your
interest, check out the following activity. It will help if you first print
yourself off a set of our NAMN star maps from
http://www.namnmeteors.org/charts.html These charts will show you the
constellations, standard stars to help in judging the brightness of the
meteors you see, and also are labeled with the standard grid lines used in
astronomy for latitude (Dec/Declination) and longitude (R.A./Right
Ascension) in the sky.
The Orionids (ORI), although having reached a maximum back on October 21st,
can be seen until about November 7th. These are fast meteors, at about 66
km per second. Although ZHR rates in October were about 20 meteors per
hour, rates in November will be low. These meteors are debris from the
famous Halley's Comet. A map showing the radiant position can be found at
http://www.imodot net/calendar/cal01.html#Orionids
The southern Taurids (STA) reach a maximum on November 5th, with a radiant
at 052 degrees, ie. RA 3h 28.2m, Dec +13 on your star map. These are slow
meteors, at about 27 km per second. They can be seen until about November
25th. ZHR rates are about 5 meteors per hour.
The northern Taurids (NTA) reach a maximum on November 12th, with a radiant
at 058 degrees, ie. RA 3h 52.2m, Dec +22 on your star map. These, like the
southern Taurids, are also slow, at about 29 km per second. They can also
be seen until about November 25th. Like the southern Taurids, a ZHR rate of
about 5 meteors per hour can be seen.
Both the southern and northern Taurids are part of the Taurid stream which
in turn has been associated with Comet Encke. For a map showing both these
Taurid radiants, check out http://www.imodot net/calendar/cal02.html#Taurids
The Taurids have a "reputation for producing some excellently bright
fireballs at times" according to the IMO.
The chi-Orionids (XOR) start to become active about November 26th, although
will not reach a maximum until December 1st, when their radiant will be at
082 degrees, ie. RA 5h 28.2m, Dec +23. These are slow meteors, at about 28
km per second. ZHR rates about December 1st should hit about 3 meteors per
hour, but will be lower prior to that. According to the IMO, this is "a
weak visual stream, but one moderately active telescopically. Some brighter
meteors have been photographed from it too. The shower has at least a
double radiant, but the southern branch has been rarely detected." A map
showing the radiant position can be found at
http://www.imodot net/calendar/cal02.html#chi-Orionids
The Phoenicids (PHO) start to become active about November 28th, reaching a
maximum on December 6th at 14.20 UT, ie. (subtracting 5 hours) 09.20 EST,
ie. 9.20 a.m. on the morning of the 6th. These are really slow
meteors, at about 18 km per second. Although the radiant is low, at maximum
down at 018 degrees, ie. RA 1h 12m, Dec -53, more southerly observers should
try to observe this shower. The ZHR rates are variable, usually only about
3 meteors per hour or less - but they have been known to reach about 100
meteors per hour! Again, one of those showers where if you snooze, you
lose! A map of the radiant can be found at
http://www.imodot net/calendar/cal02.html#Phoenicids
Lastly, the Monocerotids (MON) start to become active about November 27th,
reaching a maximum on December 8th, when their radiant will be at 100
degrees, ie. RA 6h 40.2m, Dec +08 on your star map. These are average
velocity meteors, at about 42 km per second. The ZHR rates at maximum will
only be about 3 meteors per hour, so rates in late November will be low.
For information on minor showers visible in November - and there is always
minor activity - check out Gary Kronk's "Comets and Meteor Showers" website
at http://comets.amsmeteors.org.
Besides recognized main showers, and other minor showers, there is also
sporadic meteor activity in November. 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.
This month, the phases of the moon are as follows:
Monday Nov. 4 - new moon
Monday Nov. 11 - first quarter
Wednesday Nov. 20 - full moon
Wednesday Nov. 27 - last quarter
Note that there will be a penumbral lunar eclipse on November 20th, first
contact at 23.32 UT (on the 19th), last contact at 04.01 UT (on the 20th).
It is the deepest lunar eclipse of the year - and will be visible from the
Americas, Europe, Africa and central Asia.
Planets at midmonth are:
Venus, low in morning twilight at mag. -4.3
Mars in Virgo, low in morning twilight at mag. 1.8
Jupiter near the sickle of Leo at mag. -2.2
Saturn in Orion at mag. -0.2
A star map showing the planets' positions can be printed off from
http://www.heavens-above.com - Select your location, then go to
'Whole Sky Chart'.
For information on what to record when meteor observing, check out our NAMN
Observing Guide at http://www.namnmeteors.org/guide.html
For recording sheets for your meteors, go to
http://www.namnmeteors.org/reports.html
And - if you have any questions on observing, drop a note to our NAMN
Coordinator at meteors@comcastdot net.
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4. Upcoming Meetings...
For more information on upcoming astronomy meetings, see: "International
Astronomy Meetings List" http://cadcwww.hia.nrcdot ca/meetings
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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 November...
November 2002 NAMN Notes co-written
by Mark Davis and Cathy Hall
==============================================
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