The mind-blowing video clips of the 2002 Leonid shower August 11, 2007Posted by dorigo in astronomy, personal, science.
Darn. A moonless 12th of August happens only once every three years, and – exactly as it happened three years ago – the sky is quite cloudy above my head. The Perseid meteor shower peaks unfavorably in the morning for European observers this year but still, with a clear night from my favorite observing site here in the italian dolomites, I would expect to pocket at least a hundred meteors in a few hours of observation.
Instead, I will probably be sleeping tonight and tomorrow night. You might well ask, so what ? Perseids are very well studied, we know close to everything about their orbital distribution and other details, and the data observers acquire each year, which are then collected by astronomical unions such as the UAI (in Italy) or the IMO (internationally), and then analyzed, are not going to be affected by the absence of my own risible contribution much.
Agreed. Nonetheless, I would be happy to spend four or five hours in the darkness of Passo S.Antonio, 1480 meters above sea level, in the cold and damp, straining my neck and ruining my sleep cycle, just to stare at the meteor shower. Occasionally, I would get to see a very bright meteor, which I would record in all its details. Otherwise, I would just collect 5-minute counts of the perseids, or track on gnomonic maps of the sky non-perseids, noting hour, brightness, duration, color. Most of all, I would just enjoy the show. It is a passion cultivated through more than thirty years now.
This year I will console myself – and maybe cheer a few readers up – with video clips I took in the fall of 2002, when I was treated with a huge shower of the Leonid meteors. On the night of November 17th I traveled 300 miles with two other astroamateur nutcases through Italy, in search of a cloudless spot. We ended our search on the coast of Tuscany, off the Isola del Giglio, and we saw a real show. I had a Sony digital recorder with me, and took three hours of footage. During the peak of the shower, when more than twenty meteors per minute were visible, the camera took some very nice sequences. You can see four of them here (690kb mpg), here (4.1Mb mpg), here (5.2Mb mpg – 10 bright tracks in 40″) and here (634kb mpg).
In the end, I found 173 tracks recorded on video. A little analysis allowed to determine the Zenith Hourly Rate (ZHR) of the shower as a function of time, as shown in the graph below (on the x axis are successive 5′ intervals, on the y axis is the ZHR). Remarkably, the data from thousand of observations collected by IMO (blue curve) is in excellent agreement with the points obtained by my own analysis!
Showers such as the one of 2002 are rare. We are talking about two, three hours of very high rates every few years, if you are sitting in the right spot on Earth (when it is dark, and when the sky is clear, and when there is no moon!) – and often we do not get to know beforehand whether there will be one. If you do not chase meteor showers, you are unlikely to see a big one in your whole life, no more than you are of seeing a tornado – if you don’t live in Oklahoma, that is. Seeing a tornado is something I would both love and dread. Maybe one day I will chase one of them as I do meteor showers…