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
1. Geminids - the Winter Gem...
2. Ursids, our Christmas Shower...
3. Other December Activity...
4. New Years' Alert for the Quadrantids...
5. Upcoming Meetings...
6. For more info...
The Geminid meteor shower (GEM) is the highlight of the winter season. It peaks on December 14th, but activity can be seen from about December 7th to 17th. These are beautiful meteors - and well worth braving the chilly winter night for.
The ZHR for this shower is listed as 120 meteors per hour in the International Meteor Organization's (IMO) 2005 Meteor Shower Calendar. ZHR refers to Zenithal Hourly Rate, and is the number of meteors that an observer would expect to see with the unaided eye in an hour of observing - if they are 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.
Will we have dark skies this year? No. We will have almost full moon. According to the IMO, "the major Geminids (maximum within 2h 20m of 4h30m UT on December 14)... [will be] swamped by full moonlight." However - many Geminids are bright. Regardless of the moon, get out and observe - you won't regret it. (Note that 4h30m UT on December 14th means 11.30 p.m. EST on December 13th.) Take a thermos of coffee, take your friends, and get out and enjoy this really wonderful shower!
These are average velocity meteors at about 35 km per second. A map showing where the meteors will come from in the sky can be found at http://www.imo.net/calendar/2005/fall
The parent body of the Geminid meteors 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 researchers 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."
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. If you have any questions, drop a note to our NAMN Coordinator at meteors@comcast.net
NAMN has some good star charts to mark your radiants on before you go out observing. These charts also show constellations for the whole sky, and give the brightness of a number of stars to use in judging the magnitude of the meteors you see. Our 4 printable charts can be found at 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
As winter temperatures are now with us dress warmly! The Geminids are a wonderful shower, but the nights are long and can be quite chilly. Dress in layers. Wool and polar fleece fabrics are good. Layer clothes - air in between the layers is a good insulator. For your head a warm hat and scarf are very useful. A 'balaclava' - a covering with holes for eyes, nose and mouth - will keep you even warmer.
For recording your data a small tape recorder can be useful - but take extra batteries and keep them in a warm place. Take paper and pencil as a backup - always. Take a reclining lawnchair, and get comfortable - and put an insulating mat or blanket underneath your sleeping bag as well to prevent the cold from getting at you from below. Always take extra blankets!
Clear skies for the Geminids - and send us in your observations!
The Ursids (URS) are our 'Christmas shower'! They peak on December 22nd at about 13h Universal Time (UT), which means about 8 a.m. EST for those of us in eastern North America. The Ursids can be seen from about December 17th to 26th. These are average velocity meteors at about 33 km per second. They tend to be faint.
As many people are busy with families and festivities this time of year, this shower could really use some extra observing! Just think - at a given time on one of these nights, you might be the only person in the whole world observing the Ursid meteor shower. Please - send us your data. You can make a very important contribution to the meteor researchers!
ZHR rates are quite good - about 10 meteors per hour. However, there have been several major outbursts in the past 60 years - in 1945 and 1986 - and some years with lesser but enhanced rates - 1988, 1994 and 2000. As listed on Gary Kronk's 'Comets and Meteor Showers' website at http://comets.amsmeteors.org, the ZHR rate in 1945 was 108 (from observations in Czechoslovakia) and in 1986 reached 122 meteors per hour (from observations in Norway). According to the International Meteor Organization:
"The radio maximum in 1996... might suggest a slightly later maximum time in 2005 of December 22, 15h20m UT, while the 2000 enhancement... [would be] equivalent to 2005 December 22, 15h UT... The expected peaks favor northerly sites between central Asia eastwards across the Pacific Ocean to western North America."
The Ursids have 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/2005/fall
Give yourself a Christmas treat this year - get out and see what surprises the Ursids will provide!
December is a busy time for meteor showers! If you haven't already done so, print off a set of our 4 NAMN star charts from our website 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 labeled, so you can easily mark your meteor shower radiants on them before heading out observing.
The chi Orionids (XOR) reach a peak on December 2nd but can be observed through until about December 15th. These are almost slow meteors with a velocity of about 28 km per second. There are occasional fireballs. ZHR rates at the peak will be about 3 meteors per hour. According to the IMO, this is "a weak visual stream, but one moderately active telescopically." To find out more about telescopic observing of meteors, check out the IMO website at http://www.imo.net/tele. A map of the radiant can be found at http://www.imo.net/calendar/2002
The December Phoenicids (PHO) peak on December 6th at about 8h 45m UT. For observers in eastern North America, this means 3.45 a.m. EST. They can be seen until about December 9th. This is a southern shower with a radiant at -53 degrees, but is included for those in southern latitudes. These are very slow meteors, at about 18 km per second, so will be quite distinctive. The ZHR rate is listed as variable, which means observers should always monitor the shower for unexpected activity. The rate is usually about 3 meteors per hour or less. However, back in 1956 rates did reach about 100 meteors per hour at the peak. A map of the radiant can be found at http://www.imo.net/calendar/2004/fall
The Puppid-Velids (PUP) are a southern shower lasting from about December 1st to 15th with a maximum about December 7th. These are average velocity meteors at about 40 km per second. ZHR rates are about 10 meteors per hour at maximum. This is a poorly studied shower with up to 10 substreams. Observations are strongly encouraged so the meteor researchers can use the data to learn more about this shower. Plotting is encouraged. Most of the meteors are faint, but occasionally fireballs 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) reach a peak on December 9th with activity visible through until about December 17th. These are average velocity meteors at about 42 km per second. A map of the radiant can be found at http://www.imo.net/calendar/2005/fall. ZHR rates at the peak will be about 3 meteors per hour. The meteors now are normally faint - although 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. Telescopic results of the Monocerotids suggest a peak around December 15th or 16th, from a radiant at 117 degrees, ie. RA 7h 48m, Dec +20.
The sigma Hydrids (HYD) peak on December 12th this year, and can be seen from about December 3rd to 15th. These are fast meteors at about 58 km per second. They are usually faint. ZHR rates at the peak are about 2 meteors per hour. According to the IMO, "recent data indicates the maximum may happen up to six days earlier than this theoretical maximum, which would be very much more favourable for Moon-free watching." A map showing the radiant is at http://www.imo.net/calendar/2004/fall
Lastly, the Coma Berenicids (COM) reach a maximum on December 19th with activity visible from about the 12th through to January 23rd. These are fast meteors at about 65 km per second. The ZHR rates will be about 5 meteors per hour. A map of the radiant can be found at http://www.imo.net/calendar/2004/fall
For other 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 'Comets and Meteor Showers' website at http://comets.amsmeteors.org
Besides December'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.
Planets at midmonth, and their magnitudes, for northern observers, are:
Venus -4.5 low in southwest in evening twilight Jupiter -1.7 in Virgo, low in southeast in morning sky Mars -1.3 in Aries Mercury -0.4 low in east-southeast in morning twilight Saturn 0.1 in CancerFor a sky chart showing the positions of all the planets visible this month, go to http://www.heavens-above.com, select your country, then your city, and go to 'Whole Sky Chart'.
On Sunday December 4th, Venus will be 2 degrees north of the moon - and absolutely brilliant in our winter sky. On Sunday December 25th, there will be an occultation of the bright star Spica by the moon, visible from North America except the southwest part, Central America, the Caribbean, and the northern tip of South America. On Thursday December 29th, there will be an occultation of the bright star Antares, visible from India, southeast Asia, Indonesia, the Philippines, the northern half of Australia, Fiji and West Samoa.
The phases of the moon for December are as follows:
Thurs. Dec. 1 new moon Thurs. Dec. 8 first quarter Thurs. Dec. 15 full moon Fri. Dec. 23 last quarterFor a great printout of moon phases for the month, check out http://stardate.org/nightsky/moon
For those of you busy with the holiday season and New Years' celebrations, don't forget the Quadrantids (QUA) right at the beginning of January. They can be seen from about January 1st to 5th. They peak on January 3rd at about 18h 20m Universal Time, which means 1.20 p.m. EST for observers in eastern North America (ie. daylight). It is a sharp maximum - so geographic location plays a role in the rates that you will see. These are average velocity meteors at about 41 km per second.
ZHR rates at the peak - and only for a handful of hours - are about 120 meteors per hour, but can vary from about 60 to 200 per hour. This is a hard shower to catch - but a real reward when you do.
The radiant at the peak will be at 230 degrees, ie. RA 15h 19.8m, Dec. +49, which is northern Bootes. A map can be found at http://www.imo.net/calendar/2006/winter
The favored locations for the peak will be eastern Asia and the far East. However, all observations are encouraged to monitor this shower for surprises. The telescopic meteors from this shower may peak up to 14 hours earlier, which would be about 11.20 p.m. EST on January 2nd - nighttime in North America.
June 8-14, 2006, Ostersund, Sweden... The Workshop on Impact Craters as Indicators for Planetary Environmental Evolution and Astrobiology will be held in Ostersund, Sweden. Sessions include terrestrial craters, craters on other planetary bodies, the influences of the impact on the target area, the target area on the fate of the projectile, and the properties of the impactor on the cratering process, other consequences (eg. tsunamis), environments created by the impact and their importance for life, and astrobiological aspects of impact cratering. There will be two study field trips to the Lockne Crater, and an excursion to the GeoCenter-Lockne Impact Crater Museum. For information, check out the website at http://www.geo.su.se/Lockne2006 and contact Dr. Jens Ormo of the Planetary Geology Laboratory, CSIC/INTA, Madrid, Spain at ormo@inta.es
For information on upcoming astronomy meetings, see: "International Astronomy Meetings List" at http://cadcwww.hia.nrc.ca/meetings
NAMN email: namn@namnmeteors.org
NAMN website: http://www.namnmeteors.org
Mark Davis, meteors@comcast.net
Goose Creek, South Carolina, USA
Coordinator, North American Meteor Network
Cathy Hall, chall@cyberus.ca
Ottawa, Ontario, Canada
Writer, NAMN Notes
Lew Gramer, dedalus@alum.mit.edu
Homestead, Florida, USA
Coordinator, Public Outreach
Owner/Moderator, 'MeteorObs'
Kevin Kilkenny,
namnfireball@earthlink.net
Staten Island, New York, USA
Coordinator, Fireballs and Meteorites
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Contact Lew Gramer at:
dedalus@alum.mit.edu