Leo Constellation

The meteor shower gets it’s name as the meteors appear to radiate from the Leo constellation. The best time to see the Leonids will be at around 21:30 UT on Tuesday 17th November. Conditions should be good as the moon will be just past new moon phase.

On 17th November the earth will travel through a very dense stream of debris from the comet Tempel-Tuttle. This debris stream was laid down more than five hundred and forty years ago in 1466. The earth passed through this stream in 2008 producing a good meteor shower and proving that the stream is rich in meteor producing debris. This year the earth will pass through the 1466 stream again but more to the centre and hence the 500 meteors an hour half storm prediction.

The show won’t be as impressive as the 1999 and 2001 Leonid meteor storms when 3000 meteors an hour were obeserved. That said if we have a clear night we should have a good show from the Leonids this year. Fingers crossed for a cloudless sky on Tuesday or at least that we get some sort of a break in the cloud – that’s the best we can hope from a November sky in Ireland.

Enjoy the Leonids 2009.

The meteor shower gets it’s name as the meteors appear to radiate from near the Orion constellation (the hunter). Orion has an hour glass shape and a belt of stars across the middle. The best time to see the Orionids will be after midnight as Orion will rise at around 11pm.

The Orionids are created by small particles that circle through the solar system in the orbit of Halley’s comet.  A comet has a mass that is made up of a fifty fifty combination of ice and rock. As a comet passes though our inner solar system the heat from the sun melts some of the ice and so some rock fragments no longer held by the ice fall off.  As this dust stream intersects the Earths orbit the dust fragments hit the upper atmosphere creating meteors.

These fragments are usually no bigger than a grain of sand. Some times they travel together in clumps held together by gravity.  The clumps form when the comet is near the sun. This means that in the years that the comet is close to the Earth and the sun, the meteor showers are more spectacular. Halley’s comet is at its furthest point from the Sun (and Earth) so it is unlikely that we would expect a clump with the Orionids this time round. That said if we get a clear night on Wednesday we should be able to see a good show. Clear skies are unfortunately not guaranteed over Ireland. There was a lot of cloud cover for the Perseids meteor shower but luckily a patch of cloud opened up in the right spot and just long enough for me to see three meteors. Sometimes even on a cloudy night you can get a lucky break.