2 meteor showers - one Flashy and one Humble

Samir Dhurde, 15 Nov 2007

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Click to Enlarge Map of Geminids Meteor Shower

Leonids - on Nov 18, 07

As has become commonly known to all, November brings the famous Leonids meteor shower. The peak of this shower this year is on the 18th of November, and predicted to be at 02h50m UT [UT stands for Universal Time and adding 5hr 30min to it gives us the IST equivalent] ie. in the early hours of the dawn of Sunday the 18th. A bright moon present in the Western sky may be a bit of a nuisance towards spotting the less bright streaks of light. All shower meteors can be traced back to a small area called the Radiant. For this one it is in the constellation Leo.

This event will be surely reported in newspapers as a spectacular one. But please do not be misled as this is a mild shower in which you would be able to spot about 15 meteors per hour. This shower had become quite a big event in 1999-2000 when its rate of meteors had increased. Yearly, the Leonid meteor shower results when the Earth crosses this comet's orbital plane and encounters the leftover cometary dust. That is why it is also called "the Leonid Comet". In 1998 Tempel-Tuttle passed through the inner solar system on its 33 year orbit around the Sun. Due to this, the Earth went head-on through a fresh supply of rocks and debris left by the comet Tempel-Tuttle. So, many sky-watchers were treated to an extremely active meteor shower with rates of over 100 meteors per hour! But it has gradually decreased since then and may give at best a rate of 20. However its a great opportunity for a night-out.

Geminids - on Dec 14, 07

December Brings the darling shower of all meteor watchers. The Geminids is a shower that is reliable and worth calling a shower due to its average rate nearing 100 per hour in dark places! It is not as famous as the Leonids but its flashes are much brighter and numerous, especially the beautiful green fireballs. Oddly, the parent body of this shower is not a comet but an asteroid.

This year the shower is active from December 7 to 17. The peak of this shower has been predicted to be on December 14 at 16h45m UT [translates to 22h15m IST]. So this year the event is going to peak towards the East and overhead just after dinner-time. The Moon is also absent in the sky at the peak time and hence this will be a shower to look forward to.

Observers should settle themselves at a safe dark place, away from any lights on the horizon. If you are going out, it is advisable to travel to the East of your city or town. The constellation of Gemini rises in the East and so the lights should be behind you in the West. There are other, weaker meteor showers going on around the same time as the Geminids. The best way to know if the meteor you see is a Geminid is to mentally trace the meteor trail backwards. If you end up at Gemini then you have probably seen a Geminid meteor! Refer the map above to be sure where Gemini is. Below we give some pointers at observations of these winter showers.

An all night observation is always an exciting proposition at such events. But you should be careful if you are planning to observe it, as the nights can get really cold. Go in a group and find a dark spot with open sky. Wear lots of warm clothes and carry hot drinks. Lie on a carpet to enjoy the sky-show better. Beware at places where there might be wild animals and snakes. Both showers will be seen till before dawn. Given clear dark skies, every year they produces anything from a modest 20 meteors per hour to a shower of 100! Both the radiants will be coming up towards the East. See the skymap above to recognize the pattern of stars to look towards. You can take a printout of the map wit you. On the night trip, carry a torch with red cloth or plastic on its light. In that reddish light you can read things without disturbing your dark-adapted eyes! Once sure, one can take up a project to find out the increase and decrease in rate of meteor fall. You can study hourly rates, find the position of the radiant, count the bright and dim ones etc.

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Credit :  Inter-University Centre for Astronomy and Astrophysics, Pune.

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