PDA

View Full Version : OT: Amazing cloud display



Evan
08-20-2009, 04:48 PM
I looked up to the sky yesterday as I do very frequently and in what was only a short time ago a very clear deep blue sky I saw an amazing display of very high altitude cirrus clouds. These are the highest altitude type of cloud with the only exception being noctilucent clouds.

This type are commonly called Mare's Tails and are purely ice crystals since they range to as high as 8 miles. I have done a search of the available images online and haven't found any quite as spectacular as these. I also took a long baseline stereo pair which I have arranged for parallel viewing only. It doesn't work well for some reason with crossed eye viewing.

These made for a nice addition to my collection of sky phenomena. Just 15 minutes later they were gone leaving only the deep blue sky and the very extreme UV rating we had yesterday.

http://ixian.ca/pics6/cirrus1.jpg


http://ixian.ca/pics6/cirrus2.jpg


http://ixian.ca/pics6/cirrus3d.jpg

MTNGUN
08-20-2009, 05:00 PM
Great pics, Evan. You seem to be enjoying retirement.

RKW
08-20-2009, 05:45 PM
I'm glad to hear/see that someone else appreciates weather. Nice pics!

Keith

aostling
08-20-2009, 05:56 PM
Evan,

Very impressive Mare's Tail formation indeed. I was able to fuse the stereo pair after resizing it for my monitor's dot pitch. There is plenty of stereo depth in the trees, but not much in the clouds. That's not surprising -- if the clouds are 10,000 meters distant the stereo baseline would have to be at least 100 meters for much depth to appear in the formation itself. A baseline that long would eliminate any possibility of including foreground objects.

I'm going to remember this. Now when I see some nifty clouds or sunsets I'm going to try some long baseline photos too.

Evan
08-20-2009, 06:55 PM
I can fool myself into thinking I can see some 3D in the clouds...

I used about a 20 metre baseline which was the most I could do and still capture the same scene.

mwechtal
08-20-2009, 07:06 PM
I can fool myself into thinking I can see some 3D in the clouds...

I used about a 20 metre baseline which was the most I could do and still capture the same scene.
That's exactly the type of thing you hear all the time at a star party.:) "I can almost see something just to the bottom right of center." "Yup, that's the comet. If you can't really see it, you're seeing it."

I can also see some depth in the clouds. 20M was probably a fairly good compromise. The trees fairly leap out. I've been shooting a lot of panorama's lately since I discovered AutoStitch, but I have got to try some stereo pairs too.

Langanobob
08-20-2009, 07:33 PM
Great pictures, thanks. Probably also would've made a great time lapse video over 30 compressed minutes or so. Don't think I've ever seen a sky like that. Here we have what's called the "Sierra Wave" that gives us some dramatic flying saucer (sorry, don't know the official meteorological term) shaped cloud formations and I've had fun with time lapse videos.

rantbot
08-20-2009, 08:07 PM
Here we have what's called the "Sierra Wave" that gives us some dramatic flying saucer (sorry, don't know the official meteorological term) shaped cloud formations and I've had fun with time lapse videos.
Lenticular clouds?

A.K. Boomer
08-20-2009, 10:22 PM
Double WOW, Its a good thing you were out and about, those really are spectacular and Iv never seen anything in the sky quite like that, could your cooler northern climate have something to do with that fact?

rockrat
08-20-2009, 10:52 PM
Fantastic indeed. I don't think that I have ever seen clouds similar to what you have there. We always get either the big fluffy "that looks like a three legged hyena" type clouds or we get the high solid sheet that signifies bad viewing for that evenings stargazing.

Thanks for sharing.

rock~

dp
08-20-2009, 11:04 PM
The 3D effect is very apparent and pretty cool. The wide spacing between shots has compressed the foreground quite a bit, but the background does appear to be way the hell out there as it should. Very cool clouds, btw. One of the things I miss about no longer owning an airplane is that I can no longer play among them (lower level clouds, of course :) ).

Evan
08-20-2009, 11:09 PM
Note the semi-horizontal line of cloud especially visible in the stereo pair?

It may be that these clouds are unnatural and were seeded by some sort of very high altitude aircraft. We happen to be on the orbital return path to Groom Lake.

Some years ago this video image was captured over southern BC. It isn't in the known inventory. It was being "followed" at far lower altitude by a couple of F-16s. It was shown on the evening news once and never mentioned again, in particular, not the next morning.

http://metalshopborealis.ca/pics/aurora2.jpg

Langanobob
08-20-2009, 11:35 PM
Lenticular clouds?

Rantbot, yes, I Googled and that's them. Thanks.

malbenbut
08-21-2009, 02:59 AM
I live in the north east of England and I see plenty of clouds usually low lying and dark gray. I would like to see some blue in the sky as in Evans pictures but alas its a rare sight in my region in the summer. I believed it rained every day in July at sometime and most days this month.
MBB

Black_Moons
08-21-2009, 03:52 AM
Ah those high flying clouds.. amazeing how fast they can change.. Iv seen days where the high flying clouds seem to move faster then commerical jet aircraft that often fly by.

Evan
08-21-2009, 05:45 AM
High altitude clouds can move at several hundred kilometres per hour. They live in the same regions as the Jet Stream which is a major air current that flows like a river in the sky. Commercial jets will take advantage of it when they can. I have been on flights that have arrived an hour early because of the boost from riding the Jet Stream. Happy day for the captain as it make the flight immensly more profitable.

Moxiedad2001
08-21-2009, 08:21 AM
I can see the 3D effect in the paired photos by focusing each eye on the corresponding photo. It was a handy skill for interpreting aerial photos when I worked for the Forest Service. I would call that "parallel viewing." What the heck is "crossed-eye viewing"? Kim

Evan
08-21-2009, 08:47 AM
With crossed eye viewing the position of the photos is reversed and you cross your eyes to view them. The problem with that is the brain interprets the image differently when your eyes are crossed. It expects to see things that are very close since that is what is natural when your eyes cross and that is probably why those images don't work well in crossed eye mode since the objects of interest should appear to be near infinity.

aostling
08-21-2009, 11:34 AM
I can see the 3D effect in the paired photos by focusing each eye on the corresponding photo. It was a handy skill for interpreting aerial photos when I worked for the Forest Service. I would call that "parallel viewing." Kim

Aerial stereo pairs are typically too large for parallel viewing. These are viewed in a stereoscope incorporating prisms which allows each eye to focus on a path which diverges significantly from the other eye. Eye muscles are very limited in the amount of divergence that can be achieved naturally. For strictly parallel viewing the separation of the pairs cannot exceed the interocular spacing of the observer.

Evan
08-21-2009, 12:10 PM
Eye muscles are very limited in the amount of divergence that can be achieved naturally.

It's not a muscle issue. Otherwise you wouldn't be able to look left or right with your eyes. It's strictly a matter of brain training to allow your eyes to go "wall eyed".

You can start by looking at your finger tips at about 1 foot away and fusing them at the greatest separation you can manage. I doesn't matter if they are in focus or not. Start very gradually moving them apart and re-fuse them. I can manage about 80mm while my interpupillary distance is 64mm.

As for aerial photos, you can overlap them.

aostling
08-21-2009, 01:00 PM
It's not a muscle issue. Otherwise you wouldn't be able to look left or right with your eyes.

I see your point. I didn't know it was possible to train for 80mm wall-eye. I'll have to work on this.

A.K. Boomer
08-21-2009, 02:01 PM
Evan are those clouds static charged in any way, Im just curious because now I know where iv seen this pattern before, its in those little flat screen or dome static displays that if you even put a finger remotely close to it - it forms a focal point for all the branches to meet --- if removed it looks almost identical to the patterns in your clouds, now I know wind currents play the dominant role in this situation but its so bizarre that im wondering about another influence.

Evan
08-21-2009, 03:27 PM
Perhaps. There are some very strange things that happen in the upper atmosphere that we have only recently discovered. There is an entire class of lightning phenomena that occurs between the top of thunderstorms and the ionosphere 100 kilometres up. There are Sprites, Blue Jets and Starters, Elves, Gnomes, Trolls and Pixies and more. Some of these can be seen from the ground if you know when and what to look for. The atmosphere is highly charged all the way from the ionosphere to the ground with an average potential on a clear day of as much as 900 volts per metre and when thunderstorms are around it can go to the tens of thousands of volts even with no lightning.

kc5ezc
08-21-2009, 08:46 PM
Evan: Could you list time and date for the spectacular clour pics? I'd like to forward at least one of the pics (with your permission) to the National Weather Service Storm prediction Center and the Norman, OK forecast office.
Thanks.

Evan
08-21-2009, 09:10 PM
Here is the text of my e-mail to NASA for my submission to the APOD site. Just quote me and there will be no questions about copyright.



I captured this unusually extravagant display of Cirrus Mare's Tails on August 19, 2009 at 18:55 PDT. I have been recording the sky, both day and night for many years and have never seen anything like this. They appeared from nowhere, lasted perhaps 15 minutes and dissipated as fast as they appeared. My location is in Williams Lake in Central British Columbia, Canada. The day was unusually clear and hot with a very dark blue sky at our altitude of about 800 metres. The UV rating was high extreme.

Permission is granted to use these images in any way at all as I am placing them explicitly in the public domain at this resolution level.

Evan Williams

kc5ezc
08-21-2009, 11:27 PM
Thanks Evan. I'll get the pics off to them tomorrow.
Your quote will cover the copyright issue nicely.
Thanks again for the pictures.