Aerial Leonid meteor observing campaign 2002

Observing instruction (originally prepared for sailors who contributed to the campaign in 2001 but here modified at some aspects for use by pilots and perhaps also other crewmembers and passengers of aircraft)
In November 2002, more specifically on November 19, a famous meteor shower will probably surprise many people with its display in the night skies on many locations in the world. The small interplanetary dust grains will burn completely during their entrance in the earth’s atmosphere, giving short glimpses of light, popularly called falling stars. This coming November-event is a special one.
Go to:

The basics of meteor-observations
Contacting the campain-co-ordinator
Content of Observations reports
Some interesting other meteor-internetsites could be found at:

More information on the Weerboek-site

In November 2001, several dozens of ships all over the world have contributed to observe the activity of the famous Leonid meteor shower. Especially over the areas around America and in eastern Asia many hundreds to sometimes thousands of meteors were spotted in relatively short periods (some hours). On the 19th of November 2002 again two meteoro´de-dustconcentrations are forecasted to cross the earth-orbit and are probably displaying again a magnificent celestial show.
This Leonid-meteor shower is probably the last one for the coming 97 years (maybe a smaller shower occurs in 2006). So we hope again to get the massive support of many crews aboard of all vessels (in harbour or at sea) to obtain meteor observations. It will be a ‘last’ unique possibility for many decades. Using these data, many astronomers could compute an even better meteor distribution along its path through the solar system in future. In the same way we hope to reach as many people as possible to let them know that a very rare and nice possibility of such a spectacular event will pass November 19th 2002.

Astronomers' predictions indicate that the Leonid meteor shower in 2002 could again, like in 2001, produce a lot of falling stars. It is estimated that many thousands of meteors/hour could appear in a relatively ‘short’ period if you should be on the most favourite location. The 2002-Leonid display could be a really nice event for locations in Europe and in North America. Other areas or less favourite but will still have an opportunity to watch many shooting stars.
Astronomers are therefore planning large observation campaigns all around the world.

Until 2001, observing campaigns have consisted mostly of land-based observations. Occasionally marine reports had been received but in 2001 a large observing campaign, covering the world's oceans, has been carried out. Many dozens of ships delivered valuable observations and therefore the Leonid dataset of 2001 has been greatly improved. The combined ‘meteor-counts’, from both land- and marine-based locations has lead to a detailed analysis of the dust-distribution in the Leonid meteor shower thereby contributing to a better understanding of the formation of the comet-tail of the parent Leonid-comet.

Please join the marine Leonid Observing campaign 2002 !

Ship Masters, Officers and crewmembers, and now for the first time also many crews of airliners, are invited to participate again in this 2002-observing campaign on a voluntary basis by responding to the e-mail address given at the end of this information leaflet. If your vessel is expected to be not at sea (or if you as crewmember of a plane are not in the air) during this period, it is still possible to join the campaign. When all observations have been gathered in the months after November, the outcome of the data will be published in various magazines and papers and will also be published on the Internet.

The basics of meteor-observations

Meteor astronomy is generally done by astronomy-amateurs. There are only a few professional astronomers active in meteor research today; therefore the field relies heavily on the amateurs for data. This data collected by amateurs can provide astronomers with valuable information on the origin and evolution of the Solar system. With minimal equipment, and with the knowledge of a few basic concepts, you can begin a successful pursuit of meteor observing.

Meteors, often described as ‘falling stars’, are typically small particles, normally no larger than a grain of sand, that enter our atmosphere at speeds of up to around 70 kilometres per second. They become visible at an altitude of about 100 kilometres due to their impact with the atmosphere. Most particles will evaporate from the effects of heat well before reaching the surface of the Earth. Those that do reach the surface of our planet are known as meteorites.

Although meteors can be seen on any clear night, your chances of seeing greater numbers will increase if a few key points are kept in mind. As moonlight and light-polluted skies wreak havoc upon meteors, it is preferable to observe when the moon is absent from the sky (in 2002 hardly possible during the Leonid observing period) and from the darkest skies possible. Another important consideration is the time of night when the meteor watch is held. Due to the Earth's rotation it is preferable to observe in the early morning hours. At this time you are facing the direction the Earth is travelling in its orbit. Meteors will then collide with our atmosphere. At other times, meteors must travel at a speed that allows them to overtake the Earth. (This situation is similar to a car travelling through a snowfall where more snowflakes will strike the front windshield rather than the back.)

There are two broad groups of meteors; those that arrive from random locations in the sky, which are termed 'sporadic', and others that appear to radiate from a particular region of the sky and come from meteor showers. Sporadic meteors, also known as the sporadic background, generally produce only about 5 to 10 meteors per hour, but actually make up the bulk of meteors entering our atmosphere. However the highlight for meteor observers are those nights when meteor showers are active. Although each shower is somewhat different, they normally last for several nights with a peak of activity occurring on a specific date. Your chances of observing meteors are greatly increased on a night when a shower is active as rates can range to 50 or more per hour depending upon the shower. These meteors can be distinguished from the sporadic background by the fact they radiate from one particular region of the sky known as the radiant. The Leonids in November, for example, appear to come from a location near the constellation of Leo.

Where can I see meteor showers (in particular the Leonids-2002) ?

Because meteoroid streams are always much wider than the Earth you can see meteor showers scattered over your whole sky! You don’t therefore need to face any particular direction to see a meteor shower well! Nor will a meteor shower be visible only from one area of the earth. Unlike geographically narrow astronomical events like Solar eclipses, a meteor shower will often be visible over large parts of the Earth's surface!
However, not all of Earth will be able to see a given meteor shower. This is because the bulk of our globe shields some areas of Earth's surface from the impact of meteoroid particles - in effect, some areas of the world map are always in the Earth's "shadow" with respect to any meteoroid stream. This "shadow" is bounded by the area of Earth in which a certain point on the Celestial Sphere is not visible. This special point is unique to each meteor shower, and is characterised as being the point in the sky to which all visible tracks from the shower - no matter where they are seen in the sky, or from what point on Earth - all seem to trace back to. This point is the "radiant" of a shower.

Finally, because there is often a
fine-grained structure within meteoroid streams, which the earth will "sample" as it passes through them from hour to hour, not all areas of the Earth will necessarily see the exact same show from a meteor shower! For instance, the peak activity for a particular shower may occur while it is daylight in your area of the earth. Alternatively, it may be dark during the shower's peak "maximum", but the shower radiant point may be low on your horizon, thereby reducing the number of meteors you see - or it may even be below the horizon, making it impossible to see any meteors. Watch when you know a meteor shower radiant is above the horizon. No meteors can be seen from a shower when it's apparent "radiant" is not in the sky! The radiant of the Leonid meteor shower is up by around midnight, so you're generally safe watching after then.

The Latitude of your observation position is also important. The position of the radiant of the Leonids varies from place to place and also from moment to moment. The higher the radiant is above the horizon the more meteors could be seen at the maximum-moment. At very northern latitudes the radiant is quite long above the horizon but is also staying quite low above that horizon too. In the tropics the constellation of Leo will rise high in the sky near dawn and in the Southern Hemisphere we will be confronted with the long duration of the November daylight period. Mid-Northern latitudes therefore seem to be the most favourite position, although apparently less favourite
Latitudes could also experience an impressive celestial show

Watch from the darkest site you feel safe at: this means getting away from all man-made lights, and also trying to watch when the moon is not in the sky (or is a very thin crescent). In November 2002, at the moment of the Leonid-meteor shower, the moon, unhappily, is almost full and most time present in the night-sky. Try to avoid the direct sight to the full moon during your observations, it will improve the number of observed meteors. Man-made light from several sources should be avoided if possible in order to get a truly dark sky.

Watch from a spot without obstructions, ideally on a clear night: Obviously, if there is an area of the sky you cannot see, you will miss the meteors that appear in that part of the sky! For the same reason, try facing high enough up in the sky so that no part of the horizon blocks your view. The Leonids meteor showers of recent years showed often that many bright Leonid meteors which appeared quite low above the horizon!

The cockpit-sight from planes at high altitude shows often a very transparant sky till just above the horizon, therefore a cockpit is probably one of the best places  to watch bright meteors who enter the atmosphere very far away (probably a good moment to use video equipement when this event is occurring, see the video-tip later in the instruction) !

When can I expect the meteor shower ?

The Leonid 2002 dust stream will most likely be divided into at least two main filaments. According to several computer computations the earth will cross a first filament core on November 19th at 0400 UTC. The core of a second filament is on our planet's path some 6 hours later, around 1030 UTC. According to these computations a good position for observing the first peak will be in the region of Europe and the second peak over North America.

The passage through each filament will take some hours, so the observation campaign for each filament of the meteoroid cloud will consist of at least 2 to 3 hours. However meteor counts should ideally be obtained from as long a period as possible.

The best observation periods are probably those mentioned above which are derived from computations. In reality however there may be some undiscovered filament(s) at other times in the period between 17 and 21 November (maybe already appearing from the 14th of November till the 22nd of the month). It is important therefore to be prepared for sudden increases in amounts of Leonid meteors throughout the 5 observation days. (If you have time please also report your observation counts over the ‘low-activity-time’ of the mainstream period). If you have observed the night sky and didn’t see any meteor activity, also that information is valuable for the astronomers. So if you have made an observation, always tell us what you saw, many meteors, some or no meteors, all pieces of information are even important!

It is essential that the same time zone description - UTC (GMT) - is used in your observation messages and reports.

How do I count the number of falling stars?

Scientists are eager to get counts of meteors over a specified time period, for instance 30-seconds, 1 minute- or 5-minute periods. The level of activity itself will determine which counting period should be used. If at a certain moment the number of meteors is rising quite dramatically, perhaps more than 20 meteors per minute, you should try to count the amount in small periods of 30 seconds each. Otherwise a totality count over 1-minute-periods is sufficient. If activity is low, you could make a total-count over each 5-minute-period.

What about the observing conditions ?

Another important factor is the condition of the sky at the time of observation e.g. the transparency and the amount of cloud covering the celestial bowl. Together with the meteor counts a description of the sky conditions is essential, because observations have to be compared to each other at a later date.

To estimate the amount of (thick and untransparent) clouds over that part of the sky that is visible from your viewing point, please use estimated cloud amounts in octas, on a scale from 0 to 8 octa’s. Two octas (2/8) will give a good view, six octas (6/8) some gaps in a rather obscured sky. If thin cirrus clouds cover large parts of your direct view, but still delivering a reasonable transparent sky, please note this in the “Remarks”. Observations from aircraft only have to contain information of clouds at
higher levels than the actual flightlevel !

The transparency of the night sky or at dawn can be measured by estimating which stars can be seen (try always to avoid hindering moonlight when estimating sky-transparency). If hundreds/thousands of stars are visible the sky can be said to have good transparency. In a hazy sky only the brighter stars remain visible (some dozens over the whole sky), and in very hazy or misty situations only the very brightest stars will stay in sight. Haze and fog, combined with the bright full moon, create the worst situation for meteor watching.
Ideally the magnitude of the stars that can be seen should be noted; the faintest star category that can be seen by people with good eye vision is magnitude +6 and the brightest stars reach magnitude 0 or –1.
In a bright moonlit situation a good transparent sky however will show almost no fainter stars as magnitude +4.

The brightest star like object still is planet Venus, at its most brilliant appearance reaching magnitude – 4.
The full moon is situated as –12 on the magnitude scale. These last mentioned objects sometimes are used as comparison to estimate the brightness of big fireball-meteors.

It is important to report the exact amount of total observation time. If someone is watching the sky each hour for 5 minutes, this should be noted with every beginning and end-time, for instance 1805-1810 utc ….. report nr 1 details, 1905-1910 utc…. Report nr 2 details. etc. etc.
Details of the format in which observation reports should be submitted are attached herewith. Additional observed details e.g. fireball-appearances, general brightness of meteors, etc are also welcome and can be included in the “remarks” section of your report. For aircraft observatios please write down the estimated viewing area from your observing-position (cockpit etc). See also the example at the end of this instruction.

There is no size-limit for your “Remarks”-story !

Contacting the campaign-co-ordinator.

A special e-mail address has been established for contacting the co-ordinator of the Leonid 2002 observing campaign, Jacob Kuiper, senior meteorologist at the Royal Netherlands Meteorological Institute.

This address could be used to register your participation to the campaign (without any obligation) and, from November 17th, it will automatically be used to receive your Leonid observations. (Note: From Nov 14-23 the campaign co-ordinator is not able to respond immedately on incoming e-mails because he will be in SW-Europe, leading a land-based observation team, but the email-address still should be used for sending your observations!)

It would be strongly appreciated if hardcopies of your Leonid observations should be sent to KNMI, in the Netherlands, to be sure that no valuable datasets will be lost !

The address to send your hardcopies:
KNMI, Royal Netherlands Meteorological Institute
to Jacob Kuiper.
PO-box 201
3730 AE De Bilt
The Netherlands

Some extra information for observers in aircraft at high altitude:

The Leonid shower 2002 probably contains some very bright fireballs too. The brightest meteors are that bright that they could be ‘caught’ with normal modern video equipment.
Near dawn the Leonid-radiant at northern Latitudes is rising high in the south-eastern sky. Bright meteors than appear to fall towards the horizon. From the viewingpoint of aircraft at high altitude, flying for instance in easterly direction, this will give a unique opportunity to catch them on video.
The first pass of the Earth through a dustconcentration is expected around Nov 19th at 0400 utc, at that moment planes, flying from the USA to Europe have a nice possibility to encounter this first peak when they approach the eastern Atlantic area near dawn!
The same story is occurring for planes that fly around 1030 UTC over the United States/Canada in the hours before


Content of Observation reports

Observation reports should follow the next format

*     /Aircraft Registration
A.      /Flight number and route of flight (Departure-Destination)
B.      /Name of observer
C.      /Date of observation (month, day MMDD)
D.      /Time of observation (beginning and end both in UTC)
E.       /Total number of meteors counted in that period
F.       /Position of the aircraft at beginning and at end of the observation period (latitude
      (ddmm) and longitude (dddmm) in degrees and minutes.
G.      /Altitude of the aircraft during the observation (Flightlevel)
H.      / Cloudamount in octas (0 to 8) in your viewing-sector if they are present at heights
       above the actual Flightlevel, followed by sky conditions during the observation: sky
       transparency (very good, good, marginal, poor) and/or limiting star magnitude (-1 to
/Remarks (please describe in this section also  your estimate of the part of the sky
       which could be viewed during your observation (for instance : up to 50 degr above
       horizon and over a 100 degree-sector horizontally)

If the observation consists of small one-minute or five–minute intervals (or other time periods) during the same date, the items D, E, F, G and H   and I could be repeated.

Observations can be submitted in spreadsheet format or as a listed word-document. If however messages are sent in basic ASCII-text file please use always the identifications A to I at each part of your report as in the example below.

An example of an observation report:

*  /Aircraft Registration
A /Flight KL 642 New-York - Amsterdam
B /rank and name observer
C /Nov 19th
D /0215-0235 UTC
E  /37
F /52degr04min N 038degr26min W (begin) and 52 degr36min N   032degr54min W (end)
G /FL350
H /0 octas very good
I /highest count was 10 meteors/minute at 0220 UTC

D /0305-0309 UTC
E /25

F /52degr30min N 025degr26min W (begin) and 52 degr16min N   024degr34min W (end)
G /FL350
H /0 octas good magn +4,  
I /mostly very bright meteors

D /0438-0448 UTC
E /13

F /52degr08minN 004degr31min W (begin) and 52 degr10min N   002degr24min W (end)
G /FL350
H /5 octas poor  magn +1,  
/highest meteor rate was 3 in 30 seconds, mostly thin cirrusclouds above our flightlevel.
   Viewing-sector during whole flight up to 35 degr above horizon and a horizontally viewingsector of
   approx. 60 degr always in flightdirection.

Example when this message is sent by e-mail


Flight KL 642 New-York - Amsterdam B/rank and name C/1119
D/0215-0235 E/37 F/5204N 03826W (begin) and 5236N 03254W (end)5204 G/ FL350 H/0
octas very good I/highest count 10 met.min at 0220z

D/0305-0309 E/25 F/ F /5230N 02526W (begin) and 5216N 02434W (end) G/ FL350 H/0 Oct good magn+4  I/mostly very bright meteors
D/0438-0448 E/13 F/5208N 00431
W (begin) and 5210N 00224W (end) G/ FL350 H/ 5 Oct poor magn+1 I /highest meteor rate was 3 in 30 seconds, mostly thin cirrusclouds above our flightlevel. Viewing-sector during whole flight up to 35 degr above horizon and a horizontally viewing sector of approx. 60 degr always in flightdirection.=

The message should start always with the Aircraft Registration.

The position of the aircraft should be described as in the sent message: Watch especially the              Longitude-information: degrees and minutes, together always in 5 digits!

Use always =  to show that this is the end of the message

Note: For transmitting these special messages please send them to

To be sure that no data will get lost, please send always a hardcopy of your observation to:

To Jacob Kuiper
PO-box 201
3730 AE De Bilt
The Netherlands

Some interesting meteor-internet sites could be found at:  subject Meteoren or Meteor-project, including this whole observing