Star Points for November, 2000; by Curtis Roelle East Coast Favored for Leonids Meteor Shower Observers in the northeastern U.S. have a unique opportunity to observe the Leonid meteor shower this month. Weather permitting there is a chance that we could see two consecutive peaks on the mornings of November 17 and 18. Every November in its orbit around our sun the earth crosses the orbital path of Comet Tempel-Tuttle. During each passage into the inner solar system every 33.2 years Comet Tempel-Tuttle forms a tail and through it loses quantities of dust and gas. Over time this material spreads out along the comet's orbital path to form a "debris stream" of meteoroid material. The annual passage of the earth through the debris stream produces the phenomenon known as the Leonid meteor shower which occurs near November 17-18. During an average Leonid meteor shower an observer in a dark sky location far away from artificial exterior lighting fixtures (i.e. sources of "light pollution") may expect to see fewer than 50 Leonid meteors per hour. But this year could be different. The history of the Leonids includes some of the biggest "meteor storms" ever recorded. (A meteor storm is simply a shower in which the rate exceeds 1,000 meteors per hour.) During a spectacular storm outburst in 1966 observers in the southwestern U.S. observed so many meteors that they were impossible to accurately count. The estimated rate was around 140 per second, or in the vicinity of 150,000 per hour! The Leonids are fast moving meteors that impact our upper atmosphere at a velocity of 71 kilometers per second (42 mph). When Comet Tempel-Tuttle returned in the late 1990's expectations were high for another great storm. The 1996-97 Leonids saw an increase in the number of bright meteors, many that left glowing trains which fluoresced due to ionization of the earth's atmosphere. Astronomers predicted the 1998 peak would occur over the Far East and many astronomers flocked to Asia for a good view. Unfortunately, their predictions were 16 hours off and the peak occurred over Europe. In 1999 several other tours traveled to see what was expected to be a major meteor storm. One of these tours was led by astronomer Tom Van Flandern (Meta Research, of Washington DC). He led the tour to the island of Cypress in the Mediterranean Sea based on predictions by Finnish astronomer Esko Lyytinen. The tour was a success observing a Leonid storm with an estimated rate of 5,500 meteors per hour. The success of Lyytinen's prediction was mentioned in the June issue of Sky & Telescope magazine. At the October meeting of the Westminster Astronomical Society Van Flandern presented Lyytinen's predictions for 2000. Before passing this information on I need to mention a couple of things. First, the debris trail of Comet Tempel-Tuttle is actually a collection of separate debris streams, each created by a previous passage of the comet. Thus, sometimes the earth may pass through more than one debris stream producing multiple peaks in the shower. Lyytinen is predicting that earth will pass through three distinct debris streams in 2000, two favoring the northeast U.S. and the other favoring Europe. The other point I want to make is that the meteor shower normally increases between the hours of midnight and dawn. Those who go out shortly after sunset will be disappointed. This is because of the geometry of the earth, debris streams, and their motion around and orientation to the sun. So here are the predictions for Maryland: At 2:50 a.m. EST on the morning of Friday, November 17, the Leonids will peak at a rate of some 220 meteors per hour. This is well above the average rate. The earth will be passing through the debris trail left by the 1932 passage of Comet Tempel-Tuttle at that time. Then on the following morning 24 hours later at 2:50 a.m. EST, Saturday, November 18, the Leonids will peak again but the rate will be around 700 meteors per hour! Not enough to classify it as a "storm" but pretty good without having to reserve a plane seat. At that time the earth will be passing through the debris trail left by the 1866 passage of the comet. Advice for viewing the Leonids? Dress warm, keep the outside lights off, and use a lawn chair or blankets so you can recline and look up. The Leonids may appear anywhere in the sky, but their trails will always point back toward the head of the constellation Leo the Lion. More information about the Leonids including descriptions of previous storms may be found on the Star Points web site at http://www.erols.com/roelle/starpoints/. Check out previous November installments. In other news 7:30 p.m. Wednesday November 8 is the time for the Westminster Astronomical Society's annual Telescope Buyers Workshop (TBW). This is an opportunity for potential telescope buyers to come look at equipment that is in actual use by area astronomers, in an effort to assist the holiday elves in making wise purchasing decisions. The TBW will be at the Bear Branch Nature Center north of Westminster just east of Md. 97 off John Owings Road. The event is free and open to the public. They will have a variety of telescopes and binoculars on display. These items will not be for sale but the public is encouraged to inspect them and seek answers to any questions they may have about telescopes.