One of the year’s regular meteor showers, the Leonids, happens this weekend, peaking at around 0930 on 17 November 2012. It (usually*) isn’t one of the very active showers (such as the Perseids, Geminids or Quadrantids), with the maximum rate in a normal year between 10-20 meteors per hour in perfect conditions.
The peak of the Leonids is quite broad, lasting several days, so between now and early next week it’s worth looking up to see if you can catch a glimpse of any shooting stars. The best time to view the Leonids shower is in the pre-dawn hours, but any time after 11pm on Thursday through to Tuesday night should mean you’ll see at least a few meteors.
How to see the Leonids Meteor Shower
1. Find somewhere dark with as little light pollution as possible. The countryside is best, but if you’re stuck in a city try and get away from as many lights as possible.
2. Bring a reclining deck chair. Standing outside looking up for long stretches of time gets uncomfortable.
3. Bring a blanket. It gets VERY cold outside at night in November.
4. Position yourself under your blanket on your reclining deck chair so that you take in as much of the sky as possible. Although the meteors all appear to radiate out of the constellation of Leo in the SE there’s no need to specifically face this direction as the meteors will streak across any part of the sky.
5. Wait. The rate of this shower isn’t very high, so you might only see one every five or ten minutes, maybe less often than that, so patience is a virtue.
* every 33 years the Leonids meteor shower turns into a meteor storm, in which the rates dramatically increase by a factor or 50 or more, up to perhaps several thousand meteors per hour. This regularity is due to the nature of the origin of the dust that causes these meteors. It comes from the tail of a comet, Comet Temple-Tuttle, which orbits the Sun once every 33 years. This means that the dust trail left behind by the comet – and subsequently hoovered up by the Earth to make a meteor shower at the same time every year – is refreshed every 33 years, resulting in a spike of activity for a few years afterward each pass of the comet. The comet last renewed the trail in 1998, and so the years 1999, 2001 and 2002 were all spectacular years for the Leonids, with storm rates peaking at 3000 Leonids per hour. I was lucky enough to see all of these showers, the most memorable being 2002 where in the space of just two hours under half-cloudy skies on the outskirts of Glasgow I saw over 300 shooting stars.
This morning (Wednesday 04 January 2012) at around 0530 the Quadrantids meteor shower reached its peak activity rate. According to the International Meteor Organisation the ZHR(max) was 78 +/- 7. As is usual with this meteor shower the peak was quite narrow, with activity starting to increase after 0000 on 04 January, and dropping off again by 1800 the same day.
As was predicted, observers who were out under clear skies between 0430 and 0630 would have got the best views, as within this two hour window the Moon had set and the Sun had yet to brighten the sky. The ZHR(max) of 78 was rather disappointingly low compared with the predicted maximum rate of ~120, but predicting these things isn’t an exact science. The IMO estimated that the rate usually falls somewhere between 60 and 200, so this year’s shower was certainly at the lower end of that, however that might be down to the fact that few people had clear skies (a common problem at this time of year) and so some meteors were missed.
A ZHR (max) occurring at 0530 on 04 January 2012, when the radiant was around 60° above the eastern horizon (in the UK), if seen from a cloudless dark sky site with no light pollution (i.e. a limiting magnitude of 6.5) would have meant that you’d have seen around 70 shooting stars an hour, still quite an impressive show