On Tue, 28 Jun 2011 10:46:37 +0100, Col wrote:

"Graham P Davis" wrote in message
...
On Tue, 28 Jun 2011 09:39:54 +0100, Col wrote:

I've never seen anything like this before, at the end of a dissapating
contrail there was what can only be described as a black 'streak',
perfectly straight and very noticeable. The whole effect lasted a
minute at best.

A bit of Googling (unfortunately most of it's conspiracy theory
nonsense) suggests that this is the answer:
http://contrailscience.com/contrails...es-chemtrails/ I think
the "edge shadow (volumetric shadow)" is what I saw, the contrail was
lined up with the sun.

However contrails must be crossing the sun all the time and I've never
seen that effect before. I wonder if you only see it if the sun is at
exactly the right altitude and the observer is in exactly the right
position wrt the sun & contrail.

Has anybody else seen this effect, it was definately a what the hell
is *that* moment!

Here's one I prepared earlier. ;-)

http://farm7.static.flickr.com/6059/...797844f5_b.jpg

That's exactly what I saw. I don't know whether it went right to the
horizon as there is a building blocking the view. Was that taken this
morning?

It was July last year. I was on my way to the shops for my morning paper
(or on the way back?) and saw this shadow. I almost always have a camera
tucked in my pocket and usually on a point-and-shoot setting but, even
so, the shadow had faded when I was ready. Luckily, it returned in a few
seconds so I was able to get this shot. This was the first time I'd seen
- or rather, noticed - such a phenomenon.

There are so many times when I wished I'd had a camera or better still, a
movie camera, when some unusual cloud appeared. There was the tornado I
saw about 55 years ago; unusual mammatus that I saw at a similar age
which I likened to the cloud being upside-down - cauliflower turrets
pointing downwards and surging towards each other and disappearing
upwards into the cloud; dark, thick cloud with a ragged base that turned
out to have a base of 25,000ft; patches of Ci Spi turning into what
looked for all the world like flattened-out Cu; a cirrus formation that
appeared like the ceiling of a Gothic cathedral with ribs at right-angles
to each other and with thicker patches hanging sown from the
intersections and, around the bases of these, what I can best describe as
pannus forming in moist air cooled by the falling ice crystals.



--
Graham Davis, Bracknell
Whilst it's true that money can't buy you happiness, at least you can
be miserable in comfort.