NikonGear'23
Images => Nature, Flora, Fauna & Landscapes => Topic started by: ColSebastianMoran on February 05, 2017, 17:58:53
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Woke up to a sort-of nice sunrise with an unusual feature. The vertical band. Seeking help with explanation.
This is a light pillar. Wikipedia has a good article. https://en.wikipedia.org/wiki/Light_pillar (https://en.wikipedia.org/wiki/Light_pillar).
- Sun below horizon
- Light strikes flat hexagonal ice crystals, generally oriented horizontally
- So we see the vertical band, illusion of a pillar
Question: What makes the crystals orient horizontally? If random, not horizontal, we would see a round pattern, a solar halo.
(http://2under.net/images/170130-Sunrise-Detail-IMG_8114-Scr.jpg)
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Without claiming any expertise, my understanding is the various refractive phenomena can only occur in quite narrow "windows of opportunity". These again relate to the sun elevation, atmospheric conditions, and temperature.
I live around 60 deg N and we tend to see light pillars, sun dogs, and various arcs mainly in the very deepest part of the winter, in which sun is more or less under the horizon, and frost fog and temperature inversions are formed in the lowlands. Even though conditions are conducive, these sky phenomena occurs quite seldom. There can be many years between each incident.
The manner in which the reflections and arcs are manifested are strongly dependent on crystalline particles in the air and their orientation, again relating to ambient temperature etc.
Some years ago, we had a series of light pillars showing up early afternoon, unfortunately, commencing when I was commuting home and not lasting very long. The last day I managed to catch an arc ('Moilanen' type, I'm told) just over the roof of my home. I had given up the other light shapes and was heading home in a dark mood. No more sky embellishments. Just went to my mailbox to pick up the paper and voila, the arc blazed on the sky. I had too low vantage point to get the pillar, though, as it went down not up. You cannot have it all, presumably.
Never seen anything like this ever since, not counting some sun dogs and the odd halo in winter though.
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Bjørn, thanks for the comments and the example.
I'm at 44° North. Never seen a light pillar here until this one morning last week. I remember seeing them from man-made lights in very cold conditions at other times.
Clearly you are right that it takes particular conditions to produce this reflection.
Still curious what mechanism produces the horizontal orientation of the crystals.
Again, thanks!
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Could it be as simple as the presence of a temperature inversion layer?
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It looks like it is rather the aerodynamic shape of the crystals:
http://www.atoptics.co.uk/halo/orplate.htm (http://www.atoptics.co.uk/halo/orplate.htm)
Her is an example of light pillars from man-made light sources combined with ice fog:
(http://otoien.zenfolio.com/img/s3/v41/p2196218277.jpg)
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Bjørn, isn't your image an example of the zodiacal light, rather than that of the light pillars?
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The light pillar is hidden behind my house ....
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The light pillar is hidden behind my house ....
Sorry to know that even your huge lens arsenal was not able to provide a lens to shot the subject behind something... ::)
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I was on the outside with just a camera + lens, the light was rapidly fading into dusk, and no time to enter the house, run up the stairs, and shoot from the rear balcony. An opportunity lost.
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Here are the sun reflections we observed a few afternoons in late December, 2007. A temperature inversion and biting frost created a dense ice crystalline mist over the inner Oslo Fjord and the city itself. In this screenshot (below), from a vantage point on the hillside a little higher than my digs, the 'sun dogs', a halo, a downwards pillar, and two more or less 'V' shaped arcs are seen. The middle arc is the very rare 'Moilanen arc' I photographed a few days later (Dec. 22).
http://www.atoptics.co.uk/halo/marc.htm
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Wow, that's awesome! Did you had a UV camera?
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During my stay last week in Norway, this phenomenon was visible whenever we has small ice crystals in the air.
Was seen on each of the flood lamps for the alpine skiing slope.
The picture is taken one morning on my way to set up the XC stadium for the Danish championship.
The picture is taken with my phone.
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It's the vantage point above the fjord that allow the downwards pillar to be seen. I have photographed sun haloes several times outside my district, 'sun dogs' likewise, but these peculiar arcs and pillars are more "often" (can one use this word for rare events?) seen here locally I'm told.
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Here is an Arctic variant with sun dogs and faint upwards/downwards pillars, not as spectacular as that web cam shot above with full arcs though.
At close look a few bright ice crystals can be seen floating in the air.
(http://otoien.zenfolio.com/img/s6/v140/p2196374587.jpg)
Sun dogs at Toolik Field Station.
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Shot early last week. Minneapolis, cold evening, "Light pillar" right before sunset. Handheld, no time to setup tripod. :D
(https://c1.staticflickr.com/1/522/31732921573_041f2d5265_h.jpg) (https://flic.kr/p/Qm8w2t)
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Beautiful optical effects , thanks for sharing your images
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UFO's, report to area 51... Lots of nice pics...
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I think this site is explaning it, and other haloes well. http://www.atoptics.co.uk/halo/platpill.htm
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Anirban: lovely city scape!
All others: Very interesting phenomena and documentation. Thank you for sharing!
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Some great pictures of wonderful events here, and some great info too! Learnt a lot here.
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Amazing images, guys! Thanks for sharing!
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Shot early last week. Minneapolis, cold evening, "Light pillar" right before sunset. Handheld, no time to setup tripod. :D
(https://c1.staticflickr.com/1/522/31732921573_041f2d5265_h.jpg) (https://flic.kr/p/Qm8w2t)
Beam me up, Scotty!