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. Of Transient Phenomena and Comet McNaught...
2. February Meteors for Winter Nights...
3. Upcoming Meetings...
4. For more info...
These past weeks have been a wonderful time to consider transient phenomena. Did you see Comet McNaught? If you weren't aware of this incredible comet in our (briefly) northern and then southern skies, we will assume that you were somehow temporarily lost on another world.
Congratulations go out to Robert McNaught for 'writing his name across the sky', and letting us read his 'sky diary' day by day. We have been following the photographs posted on many websites, notably at http://www.spaceweather.com - and the photos have been exquisite.
We live in an age where we can see these images every day. Before digital imaging, and photography, it took real time to be able to access the drawings and images of comets. Sir Robert Ball wrote in his "The Story of the Heavens", back in 1886:
"On the 22nd May, 1881, Mr. Tebbutt, of Windsor, in New South Wales, discovered a comet which speedily developed into one of the most interesting celestial objects seen by this generation. About the 22nd of June it became visible from these latitudes in the northern sky at midnight. Gradually it ascended higher and higher until it passed around the pole. The nucleus of the comet was as bright as a star of the first magnitude... This was the first comet which was successfully photographed, and it may be remarked that comets possess very little actinic power."
Times have changed. Many of the images of Comet McNaught were taken with digital equipment, gradually becoming more affordable to serious amateurs. Images taken in real time, and images relayed to the populace in real time. Much has been gained - but the old etchings and drawings in the historical texts still keep us fascinated and spellbound. They also provide our visual historical comparisons to great comets of the past.
It is also in the old texts that we find some of the most apropos written descriptions of comets. Somehow, modern words and brief text messages just don't cut it when trying to describe the beauty of comets - and Comet McNaught.
Camille Flammarion wrote, in his "Astronomy for Women", back in 1903:
"Glittering, swift-footed heralds of immensity, these comets with golden wings glide lightly through space, shedding a momentary illumination by their presence. Whence do they come? Whither are they bound?"
"They arrive in every direction from the depths of space, as though to reanimate themselves in the burning, luminous, electric solar centre... Attracted by some potent charm toward this dazzling focus, they come inquisitive and ardent, to warm themselves at its furnace... Their motions accelerate, they haste to plunge wholly into the radiant light. At length they burst out luminous and superb, when the day-star penetrates them with his burning splendour, illuminates them with a marvellous radiance, and crowns them with glory."
"These ethereal beauties whose blonde locks float carelessly upon the azure night are not concerned with us; they seem to have no other preoccupation than to race from sun to sun, visiting new heavens, indifferent to the astonishment they produce in us. They speed restlessly and tirelessly through infinity; they are the Amazons of space."
"What suns, what worlds must they have visited since the moment of their birth! If these splendid fugitives could relate the story of their wanderings, how gladly should we listen to the enchanting descriptions of the various abodes they have journeyed to!"
Flammarion changed the title of his book for the English translation to "Astronomy for Amateurs" - perhaps not to frighten off male readers with descriptions of Amazon comets...
History remains important though. Our studies of present comets would be lacking without all that came before. All the studies, all the drawings - and even all the marvellous descriptions.
Here's to the 'Great Comet of 2007'... may it live in our history books... and our memories.
Flammarion wrote about meteors as well:
"Sometimes, when night has silently spread the immensity of her wings above the weary earth, a shining speck is seen to detach itself in the shades of evening from the starry vault, shooting lightly through the constellations to lose itself in the infinitude of space."
"These bewitching sparks attract our eyes and chain our senses. Fascinating celestial fireflies, their dainty flames dart in every direction through space, sowing the fine dust of their gilded wings upon the fields of heaven. They are born to die; their life is only a breath; yet the impression which they make upon the imagination of mortals is sometimes very profound..."
A bit flowery on the descriptive side... but the 'celestial fireflies' part remains rather appropriate.
The alpha Centaurid (ACE) meteor shower peaks on February 8th this year at about 11h Universal Time (UT), according to the International Meteor Organization (IMO) - but activity can be seen through until about February 21st. These are fast meteors, with a velocity of about 56 km per second. ZHR rates are variable. Rates are usually about 5 meteors per hour, but outbursts of 20 to 30 per hour have occurred. Many of the alpha Centaurids are very bright, even fireballs. This is primarily a southern shower, with a radiant located at about -59 degrees on a star map, about 50 degrees south of the bright star Spica in Virgo. A map of the radiant can be found on the IMO website at http://www.imo.net/calendar/2005/winter
What is ZHR? ZHR refers to Zenithal Hourly Rate, and is the number of meteors that an observer would expect to see, on average, 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.
Although not on the official International Meteor Organization 'Working List of Visual Meteor Showers', a watch should be kept for any possible xi Bootids. These were first seen by observer George Gliba from February 5/6 to 8/9 in 1997 from the Florida Keys. These were noted as medium velocity meteors, with an average magnitude of about 3.6 and a radiant near the star xi Bootes. Xi Bootis is about 8 degrees to the left of the star Arcturus on a star map.
The delta Leonids (DLE) peak on February 25th, and can be seen from about February 15th until March 10th. At maximum the radiant will be at 168 degrees, ie. RA 11h 12m, Dec +16, which is very near the star theta Leonis, the lower right star in the triangle at the end of Leo. These are slow meteors, with a velocity of about 23 km per second. ZHR rates at maximum will be about 2 meteors per hour - but they will be quite distinctive. A map showing the movement of the radiant can be found at http://www.imo.net/calendar/2007. According to the IMO, this minor shower is probably linked to the Asteroid (4450) Pan. Both visual plotting - and telescopic observations - are encouraged.
The gamma Normids (GNO) start to become active about February 25th, although won't reach a maximum until about March 14th. These are fast meteors, with a velocity of about 56 km per second. ZHR rates at maximum will be about 4 meteors per hour, but rates in February will be lower. With a radiant about 30 degrees south of the top of the 'J' of Scorpius, this is primarily a southern shower. A map showing the radiant can be found at http://www.imo.net/calendar/2005/winter
The Antihelion Source (ANT), the ecliptical activity, produces a ZHR of about 3 meteors per hour, with an average velocity of about 30 km per second. A map showing the movement of the radiant throughout the month can be found at http://www.imo.net/calendar/2007
For other February 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 February'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 -3.8 in southwest in evening twilight Jupiter -1.9 in Ophiuchus in morning sky Mercury -0.1 low in west-southwest in evening twilight Saturn 0.0 in Leo Mars 1.3 in Sagittarius in morning skyThe phases of the moon for February are as follows:
Fri. Feb. 2 full moon Sat. Feb. 10 last quarter Sat. Feb. 17 new moon Sat. Feb. 24 first quarter
A monthly moon calendar can be printed off from http://stardate.org/nightsky/moon. For the NASA kids' calendar for the month, go to http://spaceplace.nasa.gov/en/kids/calendar.shtml
One of the simplest sky charts can be found on the website 'Heavens Above', at http://www.heavens-above.com. Ignore the 'Register' bit. Just 'Select' your country, then your city, and then scroll down the page to 'Whole Sky Chart'. Type in what day you want, and pick a time of night. Pick black on white as it's easier to read. The maps show the constellations and the positions of all the visible planets.
If you want to record visual data 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 the NAMN Coordinator at meteors@comcast.net
For visual observers, NAMN has a set of 4 star charts to help you judge the brightness (magnitude) of the meteors you see. They are also a great tool for new observers to help you learn your constellations better. The charts can be printed off from 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
The Meteoroids 2007 conference will be held from June 11th to 15th at the CosmoCaixa Museum in Barcelona, Spain, organized by the Institut d'Estudis Espacials de Catalunya.
The preliminary scientific program includes the following sessions:
1. Observational techniques and meteor detection programs
2. Meteor showers' activity and forecasting
3. Orbits of meteoroids and dust
4. Meteoroids' interactions with atmospheres
5. Atmospheric effects induced by meteors
6. Astromineralogy: properties of meteoroids
7. Interrelationships: meteoroids - IDPs - dust - micrometeorites -
meteorites
8. Meteoroid flux and impact hazard
9. Meteor studies in astrobiology
Invited speakers include Diego Janches, Pavel Spurny, Douglas ReVelle, Peter Brown, Jeremie Vaubaillon, Junichi Watanabe, Peter Jenniskens, P.A. Wiegert, I. Williams, Olga Popova, Lars Dyrud, John Plane, Nick Mitchel, Frans J.M. Rietmeijer, Jiri Borovicka, George Flynn, Matthew Genge, Donald Yeomans, Clark Chapman, M.E. Sansaturio, Jose Ortiz, Joseph A. Nuth III, Josep M. Trigo-Rodriguez, and Alessandra Rotundi.
For more information, check out the Meteoroids 2007 website at http://www.spmn.uji.es/meteoroids-2007, or contact Dr. Josep M. Trigo-Rodriguez at trigo@ieec.uab.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
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.mit.edu