"Giles" wrote in message
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On Aug 13, 3:05 pm, "Bill Grey" wrote:
"Bill Grey" wrote in message

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"Jonathan Cook" wrote in message
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On Aug 12, 9:17 pm, MajorOz wrote:
I had never experienced this before, but remember relatives talking
about foggy mountain tops producing a phenomenon called a "glory". I
don't know if this was one, but it was glorious, and lasted about an

Sounds like an awesome experience. Thanks for sharing.

Jon.

Should you find yourelf walking along a high ridge or hill when here is
an
inversion - cloud layer lower than you- the sun behind you might cast a
shadow of you onto the cloud. This is called a Brocken Scpectre, and
there may be a halo around the head of the shadow - this is called a
glory.

Google - "Brocken Spectre and Glory"

Bill

Have a look at :-http://cloudappreciationsociety.org/the-brocken-spectre/

Bill

I've seen an effect like this two or three times. A couple of things
come to mind. From the website:

"Of course, cloudspotters don’t have to climb the Brocken to see a
Brocken Spectre – any mountain can serve the purpose. Nor is the sight
of this psychadelic ghost only available to cloudspotters energetic
enough to go mountain climbing. Sometimes, the coloured rings of a
glory can also be seen around an aeroplane’s shadow, cast onto the
cloud layer below."

In fact, one need not be on a mountain or in an airplane. ANY
sufficient elevation above a cloud layer (and remember that fog is
just a very low lying cloud) will do.....a tall building, a hill, the
edge of a precipice overlooking a deep ravine, etc. But not TOO far
above, I suspect. A human being isn't going to cast much of a shadow
onto a cloud layer from thousands of feet above due to diffraction and
diffusion. The rainbow effect might (should?) still be visible
regardless (I think) but the shadow and halo would seem to require
proximity.

And then:

"It is merely an optical effect that appears when sunlight, coming
from directly behind the cloudspotter, falls onto a layer of cloud
droplets."

From the hairsplitting desk; technically, sunlight need not be coming
from behind the cloudspotter......that just makes it easier to see
unless you've got extra vertebrae in your neck that make it possible
for you to turn your head a full 180 degrees. You can stand facing
the sun and the effect will remain and be clearly visible to anyone
standing beside you and looking in the right direction. Meanwhile,
some may not have noticed or thought about it, but a rainbow ALWAYS
appears with the sunlight "coming from directly behind" the viewer, so
to speak.

Lastly:

"This optical effect is still only partially understood." Quite
possibly true, I suppose, but very surprising. No expert in optics, I
wouldn't know. However, optics is a highly developed field.....hell,
if what I've read is correct, Newton singlehandedly made it a highly
developed field nearly three centuries ago.

Anybody know exactly what is not fully understood about this
phenomenon? Anybody got any ideas about the optimum distance between
the subject/viewer and the cloud layer? Does angle of incidence have
anything to do with it? Any other atmospheric or other factors enter
into the equation?

giles


Sorry I spoke !

Bill