Satgen 501 Leonids Meteor Storm ?? by GM4IHJ (BID SGEN501) 1998-10-30 As November 17th comes around again, the media is replete with warnings of a great meteor storm which may come our way on that day. What are the chances of there being a storm ? What are the chances of seeing anything visually, or, of observing the radio effects of the storm? The chance of a great storm appears to be low. We should certainly get a good meteor shower , but a great storm as happened in 1833, while not totally impossible, is rather unlikely. The Comet which generates this debris stream which the Earth runs into every 17th of November, is called Comet Temple-Tuttle. It has an orbit which brings it in from out by the orbit of the planet Neptune, and swings it around the Sun at perigee every 33.25 years. This year the comet went through perigee around the Sun in February. So we are going to cross the meteor producing debris stream someway behind the comet. Which could reduce the chances of a major storm. Timing of the actual passage of the Earth through a comets debris stream is always problematical. Particularly with a comet which orbits as far out as Neptune and which therefore has to run the gauntlet of the tidal attractions of Jupiter , Saturn and Uranus both on its inward and outward transits - if any or all of these planets happen to be near as it passes through their orbits. The 1966 Leonids gave an excellent display , but the 1933 pass was a dud. So the suggested 1702 utc forecast time for shower maximum may be out by several hours either way. Equally important, the Radiant, the point in the sky the meteors seem to radiate from in the constellation of Leo, is below most mid latitude northern station horizons from approximately 1500 to 2230 local time . Worse still 1702 utc is daylight over North America , so if on time the peak will certainly not be visible from there. Indeed if they have clear skies Japan to India should afford the best night sky views. None the less observers elsewhere should see something. Shower activity should be present all day /night 17th utc , and some activity should be apparent on the morning of 18th November. Radio observers listening for signals from VHF stations beyond their line of sight, will be able to record activity as signals from distant stations are reflected/refracted to them via the ionized meteor trails. Indeed provided the shower radiant is near or above the receiving station horizon , rado stations should see or hear all the action whether it is day, night,cloudy or clear. So anyone who can keep a visual watch and have a radio meteor scatter detection system going at the same time should get the most complete record possible for one site. Avoiding the situation whereby a recent BBC TV show reported no results form visual only observation of the October 8th Draconids, when radio observers recorded an excellent shower from about 0900 utc to 1700 utc peaking at about 1300 utc on the 8th , ie all over in daylight for UK. Last but not least, will any satellites by damaged. Most unlikely . Several major storms over last 20 years have produced no damage reports. We may be unlucky but it is somewhat unlikely