giles@ucf-cs.UUCP (Bruce Giles) (02/25/84)
<munch munch -- a potato chip commercial - of course!>
At the beach today (well, this IS Florida!) I observed some rather
interesting phenomena around the sun. In no particular order (listed
here, that is) I saw:
(1): A ring around the sun, approximately 5 degrees out, with the spectrum
arranged as ringlets. I never saw more than a third of the ring at
one time, possibily because it was fairly faint. NOTE: red was the
inner color.
(2): About 7 degrees from the sun, a very brilliant spotch of spectrum
maybe 50% larger than the sun. Once again, red was the inner color.
Furthermore, I saw a fainter white band passing through this region
radially outward from the sun; I would say it passed from around 5
degrees out to nearly 15 degrees out.
(3): Radial bands of red, with a nearby radial band of blue-green. These
bands were by far the faintest and poorest defined of the images.
They were perhaps 1 degree wide by 5 degrees long, starting from
around 4 degrees out.
I saw items (1) and (2) together several times, but there was always a
large amount of separation between the two images. I saw (in pieces) the
full ring of #1, and saw #2 at 4 o'clock and 8 o'clock, but only those
two times. Finally, I saw #3 about 30 minutes after I last saw either
of the other two images, and no other anomolies were noticed.
The weather was: Air temp ~23-25 degrees celcius, high altitude
intermittant cloud cover, lower and heavier cloud cover at 1600, phenomena
observed from 1400 to 1500. I had difficulty observing the images because
the entire sky within about 10 degrees of the sun was a fairly bright
white. Finally, a cold front passed through the region two days ago.
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I have a fairly good idea of what caused (1) (i.e. high altitude ice
crystals), but am totally baffled as to what caused (2) and (3). *IF*
we presuppose highly alined ice crystals, I could see what caused them,
but that would (a) eliminate (1) because it requires random ice crystals,
and (b) not explain how the image would disappear from one place and
reappear 5 minutes later on the other side of the sun. (The direction of
travel was north--> south; the ground wind direction was south--> north).
Any ideas?
ave discordia going bump in the night ...
bruce giles
decvax!ucf-cs!giles university of central florida
giles.ucf-cs@Rand-Relay orlando, florida 32816mmt@dciem.UUCP (Martin Taylor) (02/25/84)
There was an excellent article on the various halos and rays that can
occur in the presence of high-level ice clouds in American Scientist
about a year ago (the cover picture shows a spectacular example).
I don't have the actual reference right now. I seem to remember that
Scientific American also had an article soem years back.
When I was a teenager I saw a spectacular series of halos and rays
that I sketched. The sketch still exists. There were two circular
halos centred on the sun, whose height was around 30 deg. I don't
know the diameter, but the inner halo grazed the horizon and the outer
one nearly reached the zenith. There were two sun-centred rays, one
horizontal and one vertical. At each intersection of a ray with a halo
there was a sun-dog that seemed almost as bright as the sun itself
(obviously wasn't, physically). Extending from each sun-dog away from
the sun was a parabolic halo. I always called it the day of the
seven suns when I referred to it. Since I had just come to Canada
from England, I thought it was a regular feature of the Canadian skies,
but I've never seen anything approaching it since.
--
Martin Taylor
{allegra,linus,ihnp4,uw-beaver,floyd,ubc-vision}!utzoo!dciem!mmtmmt@dciem.UUCP (Martin Taylor) (02/25/84)
Does anyone who lived in Northern Europe in 1950 (?) remember the
day and night of the coloured sun and moon? Where I was, the sun was
pale blue all day and the moon (about full) a rich, deep blue. People
looked sick by sunlight. Apparently in other places in England, Northern
France and Germany, and Denmark, the colours were different, ranging
from deep red through green. It was attributed to high-level dust
from forest fires in Western Canada.
Yes, Virginia, "Once in a Blue Moon" doesn't mean "never".
--
Martin Taylor
{allegra,linus,ihnp4,uw-beaver,floyd,ubc-vision}!utzoo!dciem!mmtbill@utastro.UUCP (William H. Jefferys) (02/27/84)
An excellent book which explains phenomena like these is
The Nature of Light and Color in the Open Air
by M. Minnaert (available in Dover Paperback).
Strongly recommended.
--
Bill Jefferys 8-%
Astronomy Dept, University of Texas, Austin TX 78712 (USnail)
{ihnp4,kpno,ctvax}!ut-sally!utastro!bill (uucp)
utastro!bill@ut-ngp (ARPANET)