Just some more info about the meteor shower happening this week.
These meteors (aka shooting stars) are tiny bits of debris (ice and rock dust)left by a comet called Tempel-Tuttle, which occassional crosses the Earth's orbit.
On Tuesday night/Wednesdau morning, Earth will move through this comet debris. As the debris enters our atmosphere it burns and creates a bright flash in the sky.
Each flash will last no longer than a second. Between the hours of 12am and 4am (wednesday) you might expect to see a small number of meteors (10 or less per hour).
Approaching 5am, this should increase to about 200 meteors per hour as the Earth enters the densest part of the comet's debirs field.
Remember that being in an urban environment, with brightly lit skies, we may not see the full glory of the shower but if the sky is clear it should still be quite a show.
The shower is called the Leonids because the meteor appear to originate from in front of the constellation Leo (see diagram below). Leo will be visible above the horizon after about 2am towards the East direction.
To watch the meteor shower it is best to have a clear view of the Eastern part of the sky (i.e. where the Sun will rise in the morning). Although the meteors start from the East direction they travel out in all directions so position yourself facing Eastward but kept looking high up to catch the meteors as the streak across the sky.
A star map of the east direction, on Wed 18th Nov 2009 between 3am and 5am:
(Look out for the two planet, Mars and Starn as well)