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 Post subject: Leonids 2008
PostPosted: Wed Nov 12, 2008 6:54 pm 
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Although the run of strong to storm Leonid returns seen from 1998-2002 is unlikely to repeat again until the 2030s (or perhaps even till next century), recent predictions suggest 2008 may see good to strong activity. Various possible maxima and Zenithal Hourly Rate (ZHR) strengths have been proposed, as follows. On November 17, UT timings include around 00:22 (ZHRs maybe ~130, with perhaps brighter-than-average meteors), 01:32 (due to the dust trail left by the shower's parent comet 55P/Tempel-Tuttle at its 1466 return; ZHRs very uncertain, maybe ~50, but perhaps somewhere between ~25-100) and 09h (the 'traditional' peak time based on when the Earth passes nearest the node of the comet's orbit; ZHRs possibly ~15-20). On November 18, we may encounter the Leonids' 1932 dust trail at about 21:38 UT too, perhaps with ZHRs of ~20. None of these predictions is guaranteed, of course, nor can other unexpected peaks be ruled-out!

The waning gibbous Moon around Gemini-Cancer on November 17 & 18, is about as badly-placed as possible for observers, because the shower's radiant in Leo's "head" rises only by ~23h UT, and will not reach a fully usable elevation till after midnight from Britain. Observers hoping to catch whatever the Leonids produce will simply have to brave the Moon and hope for the best, primarily on November 16-17 from the British Isles if the predictions are right. Watch as much clear sky as you can comfortably, facing away from the Moon, or blocking it behind a rooftop or wall. The shower is active from November 10-23, though the lower rates likely away from the peak night(s) may well pass unnoticed in the moonlight. Expect very swift, often trained, meteors.

For more information and a Leonid radiant chart, see the November meteor activity webpage at: http://www.popastro.com/sections/meteor ... ov2008.htm .

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)


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PostPosted: Wed Nov 19, 2008 6:56 pm 
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Sky-conditions here in SE Northumberland proved disappointing over the predicted Leonid maxima.

On the tenth anniversary of the great 1998 Leonid fireball night, November 16-17 started fairly promisingly, with a partly clear sky at sunset, but the haze which hadn't been too obvious during daylight hours became very problematic after dusk, and the sky was never better than milky all night, even before moonrise. Once the Moon was up, there was an impressive 22-degree halo round it from late evening till after 03h, bright and complete for much of the time. Unfortunately, the hazy cloud also grew thicker later. I tried a couple of extended sky-checks, firstly for five minutes either side of 23:30 (limiting magnitude, LM, a pathetic +2.8, with 10% "real" cloud at least in my view wherever I looked), but the only sky activity I saw was the lunar halo.

Given the predicted potential maximum times, I tried again from 00:10-00:35 UT, as the sky had "improved" slightly (LM +3.0, 5% cloud!), and to my surprise, I spotted two Leonids of mags +2 and 0 (with a 2-second train despite the haze) and a +1 mag sporadic in that time. The brighter Leonid shot almost overhead at 00:20 UT, an odd near-coincidence with the 00:22 UT prediction for the possible brighter-meteors peak one theorist had suggested, though scarcely significant under the conditions!

Sadly, before 01h UT, the cloud was so thick I could see no stars, nor any but the vaguest mottling on the Moon (though the halo was brighter than ever). Conditions steadily deteriorated further after this, so there was no chance for any more hopeful checking. Then November 17-18 was cloudy throughout with rain...

To keep up with how the global meteor community saw things, changing all the time at present as fresh data arrives, keep an eye on the "live" Leonids webpage off the IMO homepage, at http://www.imo.net . The pattern seems to be settling on a peak ZHR of about 90 around 02:30 UT on November 17 at its best, rather later than predicted, if it is confirmed later.

And in less than a month's time, we get to do it all again for the even more badly moonlit Geminids!

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)


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PostPosted: Thu Nov 20, 2008 11:13 am 
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Location: Bruges (just over Channel)
:shock: you must be the only one out there that night, and still detect some leonids at limited magnitude of 2.8 ! This can only be encouraged. I think to try the geminids within 3 weeks, even with a full moon...

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Thanks to the clear cold nights...


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PostPosted: Sat Nov 22, 2008 11:00 am 
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coldfieldboundary: Thanks for your comment. Actually my LM had "improved" to +3.0 when I saw the meteors! In theory, if you can see stars, you can see meteors, but of course, the fewer stars visible, the fewer meteors.

Indications are Leonid activity was surprisingly good for much of the night on November 16-17, and that may be reflected in what I was lucky in seeing.

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)


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