Monday, 8 December 2014

The Geminids

Good evening, and thanks for popping by.
Observing chances seem to be slipping me by at the moment.  The weather has been cold, calm and clear, but the moon has also been full, large and bright.  Unfortunately, it makes DSO observing a bit tricky from an already slightly light polluted location.  Nevertheless, it doesn't mean that there is no observing to be done.
This past weekend has brought the start of the annual Geminid meteor shower.  This is one of, if not, the best meteor showers of the year and happens as the earth passes through the orbit trail of an asteroid by the name of 3200 Phaethon.  The trail of dust rock particles left behind from the asteroid provide us with a peak, or Zenith Hourly Rate, of between 100 and 120 meteors an hour overnight on 13th and 14th December.  The Geminid meteors characteristically have very bright and long trails which can make for a spectacular display.  I remember watching out for them last year whilst on the way home from town one night, and counting about half a dozen or so over a 10 minute period.
This year, the moon is quite bright and just past full moon phase.  Some of the other meteor showers that we experience would be washed out by the brightness of the moon, but not these.  The chances of seeing them are still very very good.  The meteor storm is best seen from the Northern Hemisphere where Gemini is quite high in the sky during the night.
So, where do we need to look for these meteors as they are burnt up by the Earths atmosphere?  Well, contrary to popular belief, they won't happen specifically in one area of the sky.  The name Geminid is taken from the area of the sky where the meteors appear to radiate from.  That means, the part of the sky which they will appear to be travelling away from.  In this case, the radiant of the meteor shower is in the constellation of Gemini.  In truth, to see the Geminids, all you need is a clear sky with as good a view as possible all around.  To help determine if a meteor is a Geminid, I tend to face the constellation of Gemini, but look pretty much everywhere for meteors shooting away from it.
This time of the year, Gemini is in the East at around 8.30pm as the screenshot below shows,

Screenshot from Stellarium v0.12.4 showing the location of the constellation of Gemini
Now all we need is for the weather to be kind.  I will spend a bit of time looking this evening, but for the next few days, the forecast for this part of the world is a bit rotten, with a massive low pressure about to broadside the UK from the Atlantic.  I hope that this system will all blow through by the weekend and give us at least a couple of quite clear hours and chance to observe.
One day, I hope to find the time to look at building a radio detection rig for detecting meteors that can be used even when cloudy.  There are plenty of designs and information on how to around the web,  It's just a question of time, room and money!
Good luck and happy meteor spotting!

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