STAR Party: The 2007 Leonid Meteor Shower November 17, 2007

This month brings us the return of the famous Leonid Meteor Shower, a meteor display that over the past several years has brought great anticipation and excitement to sky watchers around the world.

The Leonid meteors are debris shed into space by the Tempel-Tuttle comet, which swings through the inner solar system at intervals of 33 years. With each visit the comet leaves behind a trail of dust in its wake.


Times of (prospective) peak activity:

In the Observers Handbook of the Royal Astronomical Society of Canada, meteor experts indicate that this year's peak activity should occur on the morning of Nov 18.

But while Leonid rates are unpredictable, it is unlikely that more than a dozen meteors per hour will be seen this year during peak activity, at least for viewer's with dark skies away from cities. Other meteor researchers, however, have examined Leonid prospects for this year and also suggest watching for some meteor activity on Nov 21st.

How to watch

The meteors will appear to emanate from out of the so-called "Sickle" of Leo, but prospective viewers should not concentrate on that area of the sky around Leo, but rather keep their eyes moving around to different parts of the sky.

Because Leo does not start coming fully into view until the after midnight hours, that would be the best time to concentrate on looking for the Leonid meteors.

The hours after midnight are generally best for watching for "shooting stars" anyway, because before midnight we are riding on the back side of the Earth in its orbit around the Sun, whereas after midnight we are on the front or advancing side. After midnight the only meteoroids escaping collision are those ahead of the Earth and moving in the same direction with velocities exceeding 18.5 miles per second. All others we will either overtake or meet head-on. But before midnight, when we are on the backside, the only meteoroids we encounter are those with velocities high enough to overtake the Earth.

Therefore, on the average, morning meteors appear brighter and faster than those we see in the evening. And because the Leonids are moving along in their orbit around the Sun in a direction opposite to that of Earth, they slam into our atmosphere nearly head-on, resulting in the fastest meteor velocities possible: 45 miles per second (72 kilometers per second). Such speeds tend to produce bright meteors, which leave long-lasting streaks or trains in their wake.

Leonids 2007 - activity prediction:
http://www.imo.net/calendar/2007