APOD: Ice Halos at Yellowknife (2018 Sep 14)

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APOD Robot
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APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by APOD Robot » Fri Sep 14, 2018 4:15 am

Image Ice Halos at Yellowknife

Explanation: You've probably seen a circle around the Sun before. More common than rainbows, ice halos, like a 22 degree circular halo for example, can be easy to spot, especially if you can shade your eyes from direct sunlight. Still it's rare to see such a diverse range of ice halos, including sundogs, tangent, infralateral, and Parry arcs, all found in this snapshot from planet Earth. The picture was quickly taken in the late morning of September 4 from Yellowknife, Northwest Territories, Canada. The beautiful patterns are generated as sunlight (or moonlight) is reflected and refracted in six-sided water ice crystals in Earth's atmosphere. Of course, atmospheric ice halos in the skies of other worlds are likely to be different.

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Re: APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by Tszabeau » Fri Sep 14, 2018 2:11 pm

I feel like I’m being watched.

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neufer
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Re: APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by neufer » Fri Sep 14, 2018 2:12 pm

bystander wrote:
Tue Aug 05, 2014 9:07 pm
Two Years and Counting on Red Planet
NASA | JPL-Caltech | SSE | MSL Curiosity | 2014 Aug 05

NASA's most advanced roving laboratory on Mars celebrates its second anniversary since landing inside the Red Planet's Gale Crater on Aug. 5, 2012, PDT (Aug. 6, 2012, EDT).

During its first year of operations, the Curiosity rover fulfilled its major science goal of determining whether Mars ever offered environmental conditions favorable for microbial life. Clay-bearing sedimentary rocks on the crater floor in an area called Yellowknife Bay yielded evidence of a lakebed environment billions of years ago that offered fresh water, all of the key elemental ingredients for life, and a chemical source of energy for microbes, if any existed there. ...
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Re: APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by HenryStein » Fri Sep 14, 2018 3:21 pm

It looks magnificent, nonetheless.

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Re: APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by neufer » Fri Sep 14, 2018 5:18 pm

http://www.atoptics.co.uk/halo/supinf.htm wrote:
Supralateral & Infralateral arcs

The filtered right hand simulation shows only rays which have passed through an end face and so isolates the supralateral (upper) and infralateral (lower) arcs. The unfiltered simulation at left also has a bright upper tangent arc and parhelic circle produced by the same column crystals. Some poorly oriented crystals were added to make the 22° halo. These brightly coloured arcs are usually seen only as fragments. They change their shapes dramatically with changes in solar altitude. The supralateral arc, like the related circumzenithal arc, only forms at solar altitudes below 32°. Small sections can be difficult to distinguish from the 46° halo and most of the 46° halos reported are probably supralateral arcs.
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Re: APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by Boomer12k » Fri Sep 14, 2018 11:57 pm

WoW.... interesting shot....it is interesting that the side Infralateral arc are rounded to the outside...not rounded in towards the center....

Gee, can't wait to see what 8 sided ice crystals do on another planet....

Ummm...sooooo.... where they intersect would be the pot o' gold?????

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neufer
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Re: APOD: Ice Halos at Yellowknife (2018 Sep 14)

Post by neufer » Sat Sep 15, 2018 3:00 am

Boomer12k wrote:
Fri Sep 14, 2018 11:57 pm

WoW.... interesting shot....it is interesting that the side Infralateral arc are rounded to the outside...not rounded in towards the center....

Gee, can't wait to see what 8 sided ice crystals do on another planet....

Ummm...sooooo.... where they intersect would be the pot o' gold?????
  • Gold, copper, diamonds, radioactive nuclear fuel...
https://en.wikipedia.org/wiki/Yellowknife wrote:
<<Yellowknife is the capital and only city, as well as the largest community, in the Northwest Territories, Canada. It is located on the northern shore of Great Slave Lake, approximately 400 km south of the Arctic Circle. Yellowknife and its surrounding water bodies were named after a local Dene tribe once known as the 'Copper Indians' or 'Yellowknife Indians' who traded tools made from copper deposits near the Arctic Coast. A Klondike-bound prospector, E.A. Blakeney, made the first discovery of gold in the Yellowknife Bay area in 1898. The discovery was viewed as unimportant in those days because of the Klondike Gold Rush and because Great Slave Lake was too far away to attract attention.

The Yellowknife settlement is considered to have been founded in 1934, after gold was found in the area, although commercial activity in the present-day waterfront area did not begin until 1936. As gold production began to wane, Yellowknife shifted from being a mining town to a centre of government services in the 1980s. However, with the discovery of diamonds north of the city in 1991, this shift began to reverse.

In 1978 the Soviet nuclear-powered satellite Kosmos 954 crashed to Earth near Yellowknife. There were no known casualties, although a small quantity of radioactive nuclear fuel was released into the environment, and Operation Morning Light—an attempt to retrieve it—was only partially successful.>>
Art Neuendorffer