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 Post subject: What did I see?
PostPosted: Tue May 06, 2008 11:16 pm 
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Tonight 6th May 2008, at 11.17pm.

I live in the midlands near Wolverhampton - I'd just taken the dog out and said "It's the first clear night and able to see stars clearly... a white thin streak appeared from the NNE and continued for what seamed like 2 seconds at about 80 degrees above the eastern horizon to travel to about 40 degrees above the horizon in the south. It then had grown in size and brightness. Then with the light intensity grown to very bright, it seamed to break up and disappear in an instant!

I am only just developing my interest in the night sky and so pleased to have spotted this. Was it a meteor, or space craft re entering, or what?

Did anyone else see it?

Would like to know if anyone else saw this spectacle....


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PostPosted: Wed May 07, 2008 6:00 am 
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Location: Brockmoor, nr Dudley
I'm not too far down the road from you and was out observing at the same time - there were a couple of Iridium flares visible around this time. Likely you saw one of these, I saw them too :)

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PostPosted: Wed May 07, 2008 8:06 am 
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Location: Somerset, UK
Hi Gifford

I saw something last night at around the same time only in a different direction. It went from South to North heading just to the right of the pole star. Very bright and could see it breaking up.. incredible. Could it have been the same object? What I saw certinaly wasn't an iridium (I've seen many of them). As I live in Somerset, could our different viewing locations affect its apparent movement in the sky? :?

Matt

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PostPosted: Wed May 07, 2008 11:08 am 
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Location: Ipswich, Suffolk.
Gifford said:
Quote:
it seamed to break up and disappear in an instant!


This doesn't sound like an iridium flare to me, sounds more like a meteor.

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PostPosted: Wed May 07, 2008 11:48 am 
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Location: Fraserburgh, Scotland
We are just past the peak of the eta aquariad meteor shower so it was quite likely to be one of them.

If so then you have just seen a part of halleys comet.

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 Post subject: Re: What did I see?
PostPosted: Wed May 07, 2008 1:19 pm 
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Giffard Hill wrote:
Tonight 6th May 2008, at 11.17pm.

I live in the midlands near Wolverhampton - I'd just taken the dog out and said "It's the first clear night and able to see stars clearly... a white thin streak appeared from the NNE and continued for what seamed like 2 seconds at about 80 degrees above the eastern horizon to travel to about 40 degrees above the horizon in the south. It then had grown in size and brightness. Then with the light intensity grown to very bright, it seamed to break up and disappear in an instant!


I saw it too! I was out with my dog when I thought we were lit up by a car's headlights, until I looked up and saw it. I caught it from just about overhead to where it disappeared in Leo on a N-S track. It got brighter and ended with a slight flare. 2 seconds is my guess too. The time by my dim watch was 23.15. My location, 51:49:43N 02:47:44W (4km W of Monmouth). Definitely not an iridium flare - far too fast.

Zak


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 Post subject:
PostPosted: Wed May 07, 2008 4:27 pm 
Hi

I am not an astronomer type but saw this whilst looking on the net. I too saw a large teardrop shape object with a greenish glow and a long tail heading north to south above the town of Warrington at what looked like a very steep angle. The time was just after 11.15pm. So would this be a Meteor then? Never seen anything like that before


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PostPosted: Wed May 07, 2008 6:30 pm 
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I've had quite a few reports of the May 6, 22:17 (ish) UT fireball so far from other parts of the UK. If you haven't already done so, please send me as full a report as possible, for correlation with these (and perhaps even triangulation to the trail). The minimum details I need from you are:

1) Exactly where you were (name of nearest town or large village, plus latitude and longitude ideally);

2) The date and timing of the event; and

3) Where the fireball started and ended in the sky, as accurately as possible, or where the first and last points you could see of the trail were if you didn't see the whole flight.

More advice and a fuller set of details to send are outlined on the "Fireball Observing" page of the SPA website, at:

http://www.popastro.com/sections/meteor/fireball.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 May 07, 2008 10:56 pm 
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Update on my report yeterday and my best description of sighting. I'm not experienced enough yet but I if my abilities are developing ... :oops:
May 6th at 11.17pm
* My location: Latitude = 52.52804, Longitude = -2.20893
* Urban area but sheltered from street lights
* First sight :roll: was coming from the north west not quite overhead, below Saturn, about 80 degrees above the western horizon
* Quick moving
* Single object
* Initially slightly brighter than any star visible, it progressively became very bright :shock: - white light
* Chased across the sky lasting for about 2 seconds
* No noise, travelled in a straight trajectory
* Mid track trail became visible and brightness increased
* At about 20 degrees above the southern horizon it exploded with very intensive white :D light
* In my recollection - initial size was about same size as key stars, the final size was size of a street light viewed from about one hundred yards - but much, much brighter.
* No other objects besides the normal night sky was visible i.e. not part of a shower

I am pleased that I was not the only witness :wink:


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PostPosted: Thu May 08, 2008 8:48 am 
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Location: somerset. U.K
Hi Matt, i also live in Somerset and was out observing at 11.10pm. looking for an irdium flare ( which i've never seen) according to Heavens Above one was due about that time. On the western horizon i saw a light traveling south to north its height above the horizon, was just below the moon. In then seem to fade ( just like when watching ISIS and it enters the earths shadow.)I didn't see it flare from my location, but wondered if it still could hve been an Iridium satellite.

phillj :)

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 Post subject:
PostPosted: Thu May 08, 2008 12:57 pm 
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I'm no astronomer, but could the change of light be caused by the Doppler effect.

Colours will, I am sure, change dependent on where the viewer sees the meteor and if the meteor/object was travelling towards them or away? 8)

As for the change in direction, could this be due to the angle and point of entry? Me in the being north of impact seeing it travel north to south and the person being south of impact seeing it travel south to north. :? Possibly placing point of impact above Reading? :oops:

Please... accept my apology in advance if you know my novice speculations are way off the beam :wink:


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PostPosted: Sat May 10, 2008 7:55 am 
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Giffard: No need to apologise for your inexperience. We all started out that way!

Meteor colours are an endlessly vexed question. Who sees what is heavily dependent on the individual's eyesight, as well as what colours may have come from excitiation of the meteoric and surrounding atmospheric components. The human eye isn't sensitive enough to allow specific elements or compounds to be determined from a simple visual estimate of a meteor's colour, regrettably. For more on meteor colours generally, see:

http://www.popastro.com/phpBB2/viewtopic.php?t=4712

elsewhere on the Forum.

The fact the meteor was seen in different directions from different places is entirely expected. This is what allows us to attempt triangulation to the trail, providing the various witnesses can say reasonably precisely where in the sky they saw the meteor. Of course, memory is fallible, even a few seconds after such an event, so it's quite rare to manage even an approximate trajectory estimate. It's the same parallax effect that lets anyone with normal binocular vision see in stereo, and thus estimate distances to relatively nearby objects. This is impossible for a lone observer to estimate for distant objects like meteors however, which mostly occur around 80-120 km above the surface.

I've had five separate UK reports of this May 6, ~22:15-22:17 UT fireball now, scattered across western Britain from SW England and south Wales to NW England. (If phillj's was the same event, that would make six!) The consensus so far is for a track probably trending generally north to south, maybe crudely paralleling the west coast, but I'm still hoping the various witnesses may be able to provide more accurate sky-positions to allow a better estimate for the real atmospheric trajectory.

It definitely wasn't an Eta Aquarid, as Casus Belli suggested (May 7 posting), as the Eta Aquarid radiant doesn't rise for Britain till about 02:00 UT on May 6, and would have been much too far below the horizon still at ~22:15 UT for any meteors from it to have been seen. Geometric considerations make it impossible for visually-observable meteors to occur from a radiant more than about 10 degrees below the horizon, while the lower a radiant is in the sky, the fewer meteors will be visible from it anyway. For any shower activity much below storm level (around 1000 meteors per hour or more), meteors from a sub-horizon radiant approach hen's teeth for rarity!

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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 Post subject:
PostPosted: Sat May 10, 2008 3:01 pm 
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Location: Glasgow
Giffard Hill wrote:
I'm no astronomer, but could the change of light be caused by the Doppler effect.


That would be one fast meteor! :D


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 Post subject:
PostPosted: Sun May 11, 2008 9:10 am 
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Location: Goosnargh, north of Preston, UK
Quote:
That would be one fast meteor!


Perhaps this is a good time to put meteor velocities in perspective.

Meteoroids generally meet the Earth's atmosphere at speeds between 12 kilometres per second and 71 kilometres per second (that's between 43,200 kilometres per hour and 255,600 kilometres per hour). This is fast by most standards, but even the fastest meteors are traveling at less than 0.025% of the speed of light.

Despite this, radio meteor observers do see Doppler-effects when listening to radio signals reflected from meteors. Occasionally radio meteor observers record a head-echo which, unlike the more common specular reflections, is a reflection directly from the head of the meteor. The head echo produces a descending tone heard just prior to the meteor passing through the point of closest approach for the observing system. The changing tone is due to the change in apparent radial velocity that is observed when the meteor is moving with a relatively constant linear velocity across the observer's line of sight.

I've put an example of a head echo on the following web page. These observations have kindly been provided by Belgium meteor observer Felix Verbelen.

http://www.radiometeor.plus.com/meteors/headecho/headecho.htm

For anyone wanting to know more, there is an excellent article by James Richardson and Werfried Kuneth, 'Revisiting the Radio Doppler Effect from Forward-scatter Meteor Head Echoes'.

http://adsabs.harvard.edu/abs/1998JIMO...26..117R

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