[meteorite-list] Wales: A few comments

From: (wrong string) ørn Sørheim <bsoerhei_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:23 2004
Message-ID: <200310081430.QAA07781_at_mail59.fg.online.no>

Hello List,
I'm not shure if I can go along with the Concorde interpretation
at this time, but it could be...

At least it was not 'a boring aeroplane', but rather the most special
airliner there is. And that's more than a twisting of words.

As I have written, the contrails of all the airliners I have seen,
when they have 2 or 4 engines are always *split*. They may merge togheter
more as times goes by, but one usually sees a split in the contrail
as times goes by, and at the same time the contrail get progressively
thinner.
On the Wales photos by Jonathan, one sees a non split tail, which
at the same time is thick and quite smooth (unusual), and toghether
with this, the unusual and large, abruptly ending head.
To complete the unusual, the tail is clearly twisting in a mathematically
perfect way (corckscrewing - known from meteors). I have not observed
this in airliner contrails. (See the Porthcawl image.)
In a Concorde interpretation, this might be from the suck of the
(sub?)supersonic speed, or the special form of the Concorde?

The Concorde has a smaller wingspan than other airliners of its size.
And therefore the engines are spaced more closely than the others.
This may mean that the tails merges more readily into one, but I cannot
tell for shure. I have seen no Concorde contrail in my life, probably.

Mind you, I have been fooled by a Concorde once before. On a Sunday morning
in winter time a few years ago I was wakened by a bang. I first suspected
it cuold have been a meteor, among other things. But it later turned out
it was a supersonic boom from a passover of a Concorde going over Norway
to Finland to visit Santa Claus & his reindeers...!

Anyway, I wanted a discussion of why or why not certain features of
a meteor cloud/contrail cloud points to the one or other type.
And I certainly got it! I hope we all got a little wiser.
Maybe a good thing the Concorde is grounded soon, one less
flying machine to confuse us. Our forefathers had it much easier
going when there mostly was birds up there...

About the timing of a Concorde out of Heathrow, Rob.
If your other times are correct, you missed a little added time,
which may actually strengthen the Concorde case.
That 'thing' was far out in the Bristol channel, probably halfway
to Ireland when the photo was taken. Therefore you should not
use the time of pass of Porthcawl, but out over the ocean somewhere.
Add ~5 mins and you are pretty close to 19:13 BST.

Rob, you asked about what I thought about the tilting of the
tails from the two locations. When having rotated the images quite
accurately to get alignment of clouds, I get a difference of
8-9 degrees, personally, not far from your values.

Further: Since there is obviously tilting, even though from the vantage
point of the two observers, the clouds in front are *at the
same place* my conclusion to 'the riddle' I posed earlier is:
- The clouds are very distant: At least 120 km or more!

Going over to the distance of the clouds and its consequences,
which I asked you about earlier:
- About the FOV of the Porthcawl image. My best estimate is 60x30 deg.
90 is a bit wide for a general purpose camera isn't it?
The ratio of the altitude angle of the cloud head (center), and the
vertical FOVv is about ~0.22.
For vertical FOV of 30 you get: 6.5 deg.
For vertical FOV of 45 you get: 9.8 deg.

Now for the cloud distance. I have consulted a Meteosat site on the Internet
having
IR pictures of the clouds at that time in the southwest of UK. The resolution
is not good, but there is only one band of clouds showing out there.
You clearly see a _front of clouds_ (coming in) from the ocean. It is especially
easy to see on the left of the Porthcawl image. And it's far out -
at 18:00 UT the front is about 165 km out. At 18:30 UT (half an hour between
the satellite images) it has moved somewhat more west.
Also there is the added uncertainty that there is a gathering of loosely
connected
clouds in front of the general front and the 'meteor' head. It's most
probably also
visible in the satellite images, but since the azimuth of the head and
surrounding clouds is not quite clear, the whereabouts of this feature is
unclear, but again it's clearly in front of the general front. I will choose
to use the distance of about 150 km to the 'meteor' head, since again several
things would point to the moving object being more distant than the clouds.
(If you are interested I can place the satellite images or their links on
the web.)

Now (not taking into account the earth is round, which don't add up to that
much in this connection) finding Hhd (height of 'meteor' head in km) is:
FOVv=30: Hhd=(tan 6.5)*150 km = 17.09 ~17.0 km
FOVv=45: Hhd=(tan 9.8)*150 km = 25.91 ~26.0 km

So with this cloud distance I have been using, the height of the
'meteor' head is *too high* for an airliner.
Before the Concorde option popped up yesterday (was never in my mind),
as I hinted earlier to you, I thought the distance to the clouds was pointing
towards a meteor explanation.
Now I read in my encyclopaedia that Concorde operates in a flight level
of 15-18 km, well I'm not shure anymore...

But 'the boring aeroplane' seems out, yes.

Regards,
Bjørn Sørheim
 
Received on Wed 08 Oct 2003 10:30:25 AM PDT