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(meteorobs) NAMN Notes: November 2000
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NAMN Notes: November 2000
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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://web.infoavedot net/~meteorobs
Contents:
1. Highlight of November - Leonids!...
2. Other November Showers...
3. Review of Meteor Trak Software...
4. Join the IMO...
5. Update on NAMN Member's Comets...
6. Upcoming Meetings...
7. For more info...
1. Highlight of November - Leonids!...
The highlight of November observing - and one of the highlights of the
year - is the famous Leonid meteor shower. There has been a fair amount of
discussion regarding predictions for this November 2000, both regarding
times of maximum activity and predicted meteor rates.
On November 17th, the radiant for the Leonids will be at 153 degrees, ie RA
10h 12m, Dec +22, which is in the top of the 'sickle' of Leo, several
degrees down to the right of the star zeta Leonis, the star called Adhafera.
Leonids are very fast meteors at 71 km/sec, and are active from about
November 14th to 21st.
The IMO, the International Meteor Organization, lists several predicted
times of increased activity (see http://www.imodot net/leo99/leo99index.html)
1. November 17, 7h 53m UT
due to material ejected from the parent comet in 1932
favorable for observers in North America
2. November 18, 3h 44m UT
due to material ejected from the parent comet in 1733
favorable for observers in Central and West Europe, and North Africa
3. November 18, 7h 51m UT
due to material ejected from the parent comet in 1866
favorable for observers in North America.
The IMO states that "because of the successful prediction of the 1999 Leonid
peak as presented by R. McNaught, D.Asher...there is high confidence in the
timings they gave for the 2000 Leonid peak...Unlike in 1999, more than one
trail may produce substantial activity." More details on the McNaught and
Asher predictions can be found at http://www.arm.acdot uk/leonid/index.html
The ZHR meteor rates for 2000 are estimated as "100?" meteors per hour, but
the question mark denotes the uncertainty. Much higher rates are not ruled
out.
ZHR meteor rates are for perfect conditions however. The Zenithal Hourly
Rate is the number of meteors an observer would expect to see under dark
country skies, if the 'radiant', the area in the sky where the meteors seem
to radiate from, is directly overhead. This year, we will have a moon to
contend with, so rates will be diminished. Fainter meteors especially will
be difficult to see. If Leo is low in your sky, you will also see fewer
meteors. Leo rises about midnight, so the time to see Leonid meteors is
between midnight and dawn.
Several articles to check out include:
"The Moonlit Leonids 2000" on the NASA Science News site:
http://spacescience.com/headlines/y2000/ast10oct_1.htm
"Encounter Conditions 2000-2002" on P. Jenniskens' Leonid MAC website:
http://web99.arc.nasadot gov/~leonid/1998.html
The parent comet for the Leonids is 55P/Tempel-Tuttle, which reached
perihelion most recently in February 1998. It was visible in amateur
telescopes, and was quite interesting to see knowing that it is the cause
of the spectacular Leonid meteor shower. In Gary Kronk's book 'Comets - A
Descriptive Catalog', it is mentioned that William Tempel of Marseilles
discovered the comet on December 19, 1865, in the evening sky near beta Ursa
Minoris, and described it as a circular object, with a central condensation
and a tail about 30 arcminutes long. It was independently discovered by
Horace Tuttle of Harvard College Observatory in Massachusetts on January 6,
1866. It reached a maximum brightness of about 5.0 on January 12th. It was
later determined that Tempel-Tuttle had really been discovered in China back
about October 25th, 1366, at about 3rd magnitude.
There have been many fascinating accounts of observations of Leonid meteors
over the years. One of the interesting accounts is related in Sir Robert
Ball's book 'The Story of the Heavens' printed in 1886:
"Such was the occurrence which astonished the world on the night between
November 13th and 14th, 1866. We then plunged into the middle of the shoal.
The night was fine; the moon was absent. The meteors were distinguished not
only by their enormous multitude, but by their intrinsic magnificence. I
shall never forget that night. On the memorable evening I was engaged in my
usual duty at that time of observing nebulae with Lord Rosse's great
reflecting telescope..dot it was about ten o'clock at night when an
exclamation from an attendant by my side made me look up from the telescope,
just in time to see a fine meteor dash across the sky. It was presently
followed by another, and then again by more in twos and in threes, which
showed that the prediction of a great shower was likely to be verified. At
this time the late Earl of Rosse (then Lord Oxmantown) joined me at the
telescope, and, after a brief interval, we decided to cease our observations
of the nebulae and ascend to the top of the wall of the great telescope,
whence a clear view of the whole hemisphere of the heavens could be
obtained."
"There, for the next two or three hours, we witnessed a spectacle which can
never fade from my memory. The shooting stars gradually increased in number
until sometimes several were seen at once. Sometimes they swept over our
heads, sometimes to the right, sometimes to the left, but they all diverged
from the east. As the night wore on, the constellation Leo ascended above
the horizon, and then the remarkable character of the shower was disclosed.
All of the tracks of the meteors radiated from Leo...Occasionally luminous
trains would linger on for many minutes after the meteor had flashed across,
but the great majority of the trains in this shower were evanescent. It
would be impossible to say how many thousands of meteors were seen, each one
of which was bright enough to have elicited a note of admiration on any
ordinary night..."
The Leonid meteor shower has been memorable on a number of occasions
throughout history, and warrants a special interest for all meteor
observers - professional and amateur alike.
Observers should plan to observe as many nights around the Leonid maximum as
possible in order to help study this old comet debris. The best observing
'nights' will be between midnight on Thursday November 16th and dawn on
Friday November 17th - and also between midnight on Friday November 17th and
dawn on Saturday November 18th.
This is a shower not to be missed! Observations of all kinds - visual,
photographic, video, radio - are needed by the IMO (International Meteor
Organization) in order to further study this fascinating shower. The
Leonids are one of the best showers of the year - and have the possibility
of far surpassing the rest in 2000 if unusual activity is encountered.
Plan now to get out to a country sky to observe them!
2. Other November Showers...
Orionids (ORI), although having reached a maximum on October 21st, are still
visible until about November 7th. The radiant on November 5th will be at
105 degrees, ie. RA 7h 00m, Dec +17, which is about 5 degrees left of the
star gamma Gemini, the star Alhena. These are fast meteors, with a velocity
of about 66 km/sec and are debris from Halley's Comet. Although ZHR rates
at maximum are quoted as about 20 meteors per hour, rates away from the
maximum will be minimal.
The southern Taurids (STA) reach a maximum on November 5th, with a radiant
at 052 degrees, ie. RA 3h 28.2m, Dec +13, which is near the star 5 Tauri on
an atlas, about halfway between the horns of Taurus and the head of Cetus.
These are slow meteors, at about 27 km/sec, and ZHR rates are about 5
meteors per hour.
The northern Taurids (NTA) reach a maximum a week later, on November 12th,
with a radiant at 058 degrees, ie. RA 3h 52.2m, Dec +22, which is about 3
degrees down to the left of the Pleiades on an atlas. These are also slow
meteors, at about 29 km/sec, and ZHR rates about 5 meteors per hour.
Both Taurid streams are related, and have a possible association with a
group of objects, including Comet Encke. Both northern and southern Taurids
can be seen until about November 25th.
The alpha Monocerotids (AMO) reach a maximum on November 21st, but can be
seen from about November 15th to 25th. Their radiant at maximum is at 117
degrees, ie. RA 7h 48m, Dec +01, which is about 5 degrees down to the left
of the bright star Procyon in Canis Minor. These are fast meteors, at about
65 km/sec. Rates are variable, but well worth monitoring. This shower has
experienced outbursts of hundreds of meteors per hour on occasion. Get out
and see what it does this year!
The chi Orionids (XOR) start to become active in late November, and will
reach a maximum on December 1st. They can be seen from about November 26th
to December 15th. On December 1st, the radiant will be at 082 degrees, ie.
RA 5h 28.2m, Dec +23, which is about 2 degrees up to the right of M1, the
Crab Nebula, and about 5 degrees south of the star beta Tauri, also known as
Alnath. These are slow meteors at about 28 km/sec, and will reach a ZHR
rate of about 3 meteors per hour at maximum.
Lastly, the Monocerotids (MON) can also be seen the last couple nights of
November and will reach a maximum on December 9th. They can be seen from
about November 27th to December 17th. On November 30th, the radiant will be
at 091 degrees, ie. RA 6h 4.2m, Dec +8, which is about 2 degrees to the left
of the star alpha Orionis, better known as Betelgeuse. These are average
velocity meteors, at about 42 km/sec. ZHR rates at maximum will reach about
3 meteors per hour, so rates in late November will be low.
Basic star charts for you to use to mark your meteor radiants on can be
found at: http://web.infoavedot net/~meteorobs/charts.html These charts also
provide you with a set of 'standard stars' to use in judging the brightness
of the meteors you see.
For additional use in judging magnitudes, the planets' brightness' are
as follows, to the nearest half magnitude at midmonth:
Venus, low in southwest after dark -4
Jupiter, in Taurus, up all night -3
Saturn, in Taurus, up all night -0.5
Mercury, low in southeast in morning 0
Mars, in Virgo, rises about 3 am +1.5
For November, phases of the moon are as follows:
Sat. Nov. 4 - first quarter
Sat. Nov. 11 - full moon
Sat. Nov. 18 - last quarter
Sat. Nov. 25 - new moon
To see what times various satellites and the International Space
Station (ISS) are passing over your location, check out
http://www.heavens-above.com
If you are new to meteor observing, check out our NAMN Observing Guide at
http://web.infoavedot net/~meteorobs/guide.html
For more advanced information, and information on southern showers visible
this month, see the website of the IMO, the International Meteor
Organization, at www.imodot net.
3. Review of Meteor Trak Software...
Meteor Trak v1.0 as reviewed by Mark Davis:
I have been fortunate to be able to put this computer software through its
paces for nearly a year. In a nutshell, I can report that this is a very
fine program, and will be useful to meteor observers with an inclination to
record their observations via the family computer.
Meteor Trak is a Windows 3.1/95/98/NT compatible program that allows a user
to record and analyze data obtained from their meteor observations. Data
entry can be made after the watch, or for owners of a laptop computer, in
real time while observing. This can be done without destroying the dark
adaptation of your eyes as the software comes with a nighttime mode.
The features of this software are too numerous to mention here. Some of the
most useful ones I found included the capability to produce a zenithal
hourly rate analysis and magnitude distribution, and the ability to print
report forms used by various meteor groups including NAMN. Another useful
feature, mentioned above, is the ability to enter data later at your desk,
making it possible to enter prior observations.
Sci-Trak Software maintains an informative website devoted to the product
and provides support in the form of add-on programs. Currently, these
include a time utility and several meteor forms. Meteor Trak is available as
a download from the Sci-Trak website and at a cost of $24.95, and is well
worth the price. For more information about Meteor Trak, visit the website
at
http://www.sci-trak.com.
4. Join the IMO...
This time of year tends to bring renewals to memberships and astro
magazines. If you are not already a member of the IMO, give it serious
thought!
The IMO, the International Meteor Organization, is for all of us - amateurs
and professionals alike. Membership includes a great bimonthly publication,
with articles ranging from the technical aspects of meteors all the way to
the fascinating history of various meteor showers. It is illustrated with
lots of diagrams and photographs, and is both very readable for the amateur,
and very informative for those with a more professional interest.
Membership rates for the IMO are listed below. For North Americans, a U.S.
check or money order should be mailed to Mr. Robert Lunsford, IMO
Secretary-General, 161 Vance Street, Chula Vista, CA 91910, with the check
made payable to "Mr. Robert Lunsford".
Membership rates:
$20 U.S. - regular - with newsletter by surface mail
$40 U.S. - regular - with newsletter by airmail
$40 U.S. - combined - with newsletter, fireball reports, report series by
surface mail
$65 U.S. - combined - with newsletter, fireball reports, report series by
airmail.
Rates are expected to increase in 2002, so observers are encouraged to renew
now for 2 years. If paying for 2001 and 2002, the rates will be $40, $80,
$80, and $130 respectively - but will save you money over the next couple
years.
For more information, check out the IMO website at www.imodot net
5. Update on NAMN Member's Comets...
NAMN member Mike Boschat of Halifax, Canada is now up to 16 comet
discoveries, all found by analyzing the computer images posted on the
website for the SOHO orbiting solar observatory! Congratulations Mike!
Mike recently took a look at where the majority of the SOHO comet
hunters are located around the globe. He found the following number of
observers: 3 in each of Germany and the U.S., 2 in Britain and the USSR,
and 1 in each of Australia, Canada, France and Italy. In Mike's own words
"So the majority are in Europe. To be the first to report one has to stay up
all night or try to get a "window" when they are sleeping...!"
To check out details of Mike's comet finds, visit his website at
http://www.mscs.daldot ca/~andromed.
6. Upcoming Meetings...
August 6-10, 2001 - Sweden:
The Meteoroids 2001 conference will be held at the Swedish Institute of
Space Physics in Kiruna, Sweden. Topics covered will include historical
observations and perspectives on meteoroids; dynamics, sources and spatial
distribution; detection and characteristics of meteoroids from interstellar
space; the meteoroid interaction process in the atmosphere;
hypervelocity impact effects on spacecraft; Leonid meteor storms; optical
observations of meteors; and meteor radar work. For more information,
contact Asta Pellinen-Wannberg at asta.pellinen-wannberg@irf.se and check
out the conference website at http://www.irf.se/Meteoroids2001/
September 20-23, 2001 - Slovenia:
IMC 2001, the annual convention of the International Meteor Organization,
will be held northwest of Ljubljana, in a mountain resort in the Julian
Alps. This is a worldwide meeting for all amateur meteor observers - not
just for professionals. Slovenia is on the Adriatic Sea, just east of the
top of Italy, and on the southern border of Austria. North American
observers are particularly encouraged to consider taking a vacation to
Europe next year to attend. It is a wonderful opportunity to get to meet
observers from around the globe - and to see some of the most scenic parts
of Europe at the same time! For more information, check out the IMO website
at www.imodot net.
7. For more info...
Contact:
Mark Davis, MeteorObs@charlestondot net
Goose Creek, South Carolina, USA
Coordinator, North American Meteor Network
And check out:
NAMN home page:
http://web.infoavedot net/~meteorobs
Back issues of NAMN Notes can be found on-line at the NAMN website, and in
the meteorobs archives at:
http://www.tiacdot net/users/lewkaren/meteorobs
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:
owner-meteorobs@jovian.com
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Here's to 'Clear Skies' for November...
November 2000 NAMN Notes co-written
by Mark Davis and Cathy Hall
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