Leonids from terry (well a mail about them...!)

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Hi all,

1. It's not often you get an email from me sent just before 7 a.m.! But I happened to be awake & heard the 06.30 BBC Radio Ulster News describe a "Meteor Storm" to be expected later tonight (Fri 19 Nov). Shortly after, one of the presenters did an interview with a spokesman for the Royal Astronomical Society, whose name I will omit, about the expected "storm". I was so perturbed at this that I got up & sent out the email! (They ran the headline story again on the main 7a.m. News.)

This was, I presume, based on a Press Release from the RAS, about the possibility of some unusual 'late' Leonid meteor activity. As you all know the Leonids come every November, usually around Nov 17. But various astronomers, including Dr David Asher at Armagh, had predicted the possibility of some enhanced activity on Nov 19/20, after the shower would normally have ended. So far so good - David's record on such predictions is impeccable! But neither David, nor any of his colleagues, described the possible level of activity as a storm! In fact, the predicted level is only about 10 meteors per hour! That's not even a decent normal annual shower level! Nor did they say it would be visible from UK/Ireland - the best place to see it would be much further East. In fairness, the RAS spokesman did refer to this.

But he did also say in the interview that there were two possible times to see these 'storm' meteors from here - from 9.30 to 10 p.m., and around midnight. It was the first of these that got my goat! The radiant will be WELL below our horizon even at 10 p.m., so we wouldn't see anything! Even from far Eastern England, the radiant won't have risen by 10 p.m. So there simply won't be any Leonids visible from the UK at that time. And we in Ireland are furthest away in the British Isles from even the remote possibility of seeing anything. If someone from the RAS does not realise that, there's not much hope for popularising astronomy!

It's loose, misleading statements like that which can get astronomers a bad name among the public - somebody raises expectations, people go out and observe and see nothing and get totally disillusioned, and don't pay any attention to future, realistic, predictions.

Even at the second time mentioned, 'around midnight', the level of activity would be barely above the normal background rate, and would not even be noticed by the casual observer! At this time of year we get around 10 meteors per hour from the sporadic background every night! Of course you'll only see that rate from a very clear dark sky! And with the Leonid radiant so low, a nominal rate of 10 Leonids per hour would translate to about 1-2 per hour actually observable!

Anyway to call a possible maximum (ZHR) rate of 10 per hour a "meteor storm" is grossly misleading! Perhaps the word "storm" originated with the BBC, but it didn't sound like it! The accepted definition of a storm is at least 1000 meteors per hour, so 10 hardly qualifies!

And just to emphasise the difference, we do expect a really good meteor shower (but not a storm) from the Geminids in December - best activity on the night of 13/14 December when rates might reach 80 per hour - so I hope that this 'False Alarm' wll not put people off.

I'm glad to note that after I sent out my email this morning (which went to all my media contacts), the BBC stopped running the story, so maybe it was worth getting up so early!

To sum up: we just MIGHT see some slight activity from the Leonids, after the shower would normally have ended, at around, or shortly after, midnight tonight, but don't expect anything spectacular! In fact, the level of activity is expected to be so low here that I hadn't even issued an alert about it.....

(More on the Geminids closer to the time, of course!)

2. However, to compensate for the lack of Leonids, we are currently being favoured with the start of another series of evening passes of the ISS. As I'm sure you know, it appears as a bright moving star, sometimes nearly as bright as Jupiter, crossing the sky over a period of a few minutes, generally from West to East. The times vary from night to night, but you can get up to date predictions for your location from <www.heavens-above.com> For example, there's a good one at about 18.10 for Belfast on Saturday night: times in other areas will vary by up to 10 minutes.

Clear Skies,

Terry Moseley

And the unhyped AI message (sorry couldnt resist!):

Leonid Shooting Star Shower AND Space Station to blaze across Irish skies this week

The next few nights should see the number of shooting stars ("meteors" to give them their proper name) visible in the sky increase by a factor of ten as the annual Leonid meteor shower reaches its peak activity.

Tuesday night, the very best night, should see up to 50 Leonids per hour. They can be seen anywhere in the sky but their paths all point back towards the constellation of Leo, hence the name.

For best viewing, watch until after midnight and try to get away from streetlights which brighten the sky and make the natural celestial fireworks display harder to see.

The shower lasts for several days and recently a second surge of activity has been predicted for Friday nights. Members of the public would be well advised to watch on every clear night this week.

Further details from Astronomy Ireland's Newsline on 1550-111-442 (calls cost 95c/min) or order our magazine here

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
18 years 4 months ago #5946

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Your snippet from AI was cut short and left out the address where I could get the Magazine.. :cry:

Shocking for the Beeb to be running duff info - glad you put them right, especially before most people were up. Well, me at least... Its a shame RAS could get it so wrong. What can be done about it? Can you mail them or the unnamed source?

18 years 4 months ago #5947

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Replied by dave_lillis on topic Re: Leonids from terry (well a mail about them...!)

only 95c a minute, thats a steel :lol:
Dave L. on facebook , See my images in flickr
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Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor
18 years 4 months ago #5956

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Dave - that's a steal alright - daylight bloody robbery if you ask me, especially given that the info is free elsewhere... :!:
18 years 4 months ago #5963

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