Aerial
Leonid meteor observing campaign 2002 |
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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 earths 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 meteoroïde-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 dont 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) ! Remarks There is no size-limit for
your Remarks-story !
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