Observing campaign : Leonids 2007
Those last year manage to raise the Leonids up to the range of mythical showers, with activity maxima reaching up to more than 2000 meteors per hour observable with the naked eye! But what will happen this year?
It seems unfortunately that the Great Show of the leonids has come to an end... If last year, the activity raised to more than a hundred Leonids per hour, nothing similar is predicted for 2007. We should just observe a "classical"Leonid return this year, that means 10 to 15 meteors per hour at best.
But even if it's right those rates are far from those observed from 1998 to 2001, and then 2006, the Leonid shower is always an interesting stream to monitor! Even if the forecasts (now very accurate) don't predict anything exceptionnal!
First because with hourly rates superior to 10, the shower is always a medium activty one, which is not too boring to watch at (one Leonid every ten minutes).
Second because the Earth, even if it won't cross a dust trail let by 55P/Tempel-Tuttle, will come very close to the 1932 trail during the 18-19 November night (thank you Michel for the correction!), just before 0h UT, according to J. Vaubaillon's predictions. Even if this event is not well situated for European observers, as the radiant won't be above the horizon at that time, it means that unexpected activity can always occur!
The Leonid radiant is situated in the head of Leo. Just have a look at a sky chart or a sky software, and you'll see that it only rise after midnight. That falls very well this year, because at the same time, the Moon will set! The radiant will thus culminate at the end of the night, and conditions are becoming better and better as time passes. It's then ideal to observe from 3 to 4h UT, to benefit from dark skies and the height of the radiant, during 17-18 and 18-19 November nights. The first night corresponds the "classical" activity peak predicted by the IMO. The second one is related to the 1932 dust trail evocated above (that night, do not hesitate to begin observing sooner, in case some part of the trail produce residual activity when the radiant will rise).
Leonids are very swift meteors: their atmospheric reentry speed of 71 km/s shows that they are among the fastest meteors of the celestial voute. At the end of the night, if the Sun is well under the horizon, watch the maximum of Leonids in the direction of Auriga. or you can direct it more to the North, in the region of the Little Dipper.
Every observing method can be used, even if photographic results will mainly depend on the activity of the stream during the maximum. Radio observations will allow the following of the activity of the stream, even when the Sun will have raised. They won't be able, unfortunately, to confirm or infirm the crossing more or less deep of the 1932 dust trail.
Clear skies to all!
And don't hesitate to let us know about your results!