APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

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APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by APOD Robot » Wed Jul 20, 2011 4:05 am

Image Noctilucent Clouds Over Edmonton

Explanation: Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Normally too dim to be seen, they may become visible at sunset during late summer when illuminated by sunlight from below. Noctilucent clouds are the highest clouds known and thought to be part of polar mesospheric clouds. Pictured above earlier this month, a network of noctilucent clouds cast an eerie white glow after dusk, above the the city of Edmonton, in Alberta, Canada. Much about noctilucent clouds has been discovered only over the past few years, while how they form and evolve remains a topic of active research.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Beyond » Wed Jul 20, 2011 4:17 am

The almost square sunset is really nice. The shape reminds me of the really big fuel storage tanks with the floating tops. Except, they're not orange.
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Ann » Wed Jul 20, 2011 6:27 am

APOD robot wrote:

a network of noctilucent clouds cast an eerie white glow after dusk
Well, they look mostly blue to me. Certainly when we compare them with the almost shockingly yellow-orange light of the streetlamps. Pictures like this remind you of how non-white most of our artificial illumination is.

It's a beautiful APOD, and noctilucent clouds are a lovely sight.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Star*Hopper » Wed Jul 20, 2011 10:22 am

*YAWN*
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Indigo_Sunrise » Wed Jul 20, 2011 10:29 am

Four links of the words, 'Noctilucent Clouds', and two of them are the same....?


:|
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by orin stepanek » Wed Jul 20, 2011 12:43 pm

I rather like the picture! 8-) :D
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by neufer » Wed Jul 20, 2011 12:52 pm

Ann wrote:
APOD robot wrote:

a network of noctilucent clouds cast an eerie white glow after dusk
Well, they look mostly blue to me. Certainly when we compare them with the almost shockingly yellow-orange light of the streetlamps.
Pictures like this remind you of how non-white most of our artificial illumination is.
It's those damn astronomers who to blame. Let's go burn down an observatory :!:
http://en.wikipedia.org/wiki/Street_light wrote:
<<In urban areas light pollution can hide the stars and interfere with astronomy. In settings near astronomical telescopes and observatories, low pressure sodium lamps may be used. These lamps are advantageous over other lamps such as mercury and metal halide lamps because low pressure sodium lamps emit lower intensity, monochromatic light. Observatories can filter the sodium wavelength out of their observations and virtually eliminate the interference from nearby urban lighting.>>
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by bystander » Wed Jul 20, 2011 2:26 pm

Indigo_Sunrise wrote:Four links of the words, 'Noctilucent Clouds', and two of them are the same....?
Here's some more!

The Mystery and Beauty of Noctilucent Clouds
Discovery News | Mark Thompson | 2011 Jun 10

Noctilucent Clouds and A Bright Northern Star
Universe Today | Adrian West | 2011 Jun 30

Stunning Noctilucent Clouds Shine Brightly in the UK
Universe Today | Nancy Atkinson | 2011 Jul 01
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by DDSD » Wed Jul 20, 2011 2:28 pm

Gee-we have a picture of clouds--lets see 43 years ago today I sat up and watch man walk on the moon--in 42 years NASA hasnt done anything outside of taking pictures and wasting money on low earth orbit. Just think-we have NOT put a man on Mars-42 years, and we still have never put a man on any other planet. And on December 7, 1972-we last walked on the Moon, that was nearly 40 years ago-Man has failed to get to Mars. Today would have been a good day for something like this instead of clouds.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by orin stepanek » Wed Jul 20, 2011 3:04 pm

I hope we someday go back to exploring the moon; but no rush! Just think; on the moon there are no clouds; no gray skies to turn blue. No shade trees; no rivers; no houses; no factories; no neighbors! Only stark emptiness. :? Might be a nice place to visit; but I wouldn't want to live there. :shock:
Orin

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by nstahl » Wed Jul 20, 2011 3:25 pm

Information about the Solar System is good, getting men and women generally safely to the asteroids and Mars would be good. Ultimately it will be vital. People who refuse to pay their fair share of taxes are bad.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by kaigun » Wed Jul 20, 2011 5:01 pm

According to the wikipedia link at 61 degrees N I live in the perfect zone to see these clouds, but if I have, I didn't realize what I seeing. I see it also says they are best when the Sun is between 6 and 16 degrees below the horizon. At these latitudes in the early summer, that is going to be after midnight.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Ann » Wed Jul 20, 2011 5:13 pm

neufer wrote:

It's those damn astronomers who to blame. Let's go burn down an observatory :!:
Like the good citizens of Springfield?

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by bystander » Wed Jul 20, 2011 5:18 pm

kaigun wrote:According to the wikipedia link at 61 degrees N I live in the perfect zone to see these clouds, but if I have, I didn't realize what I seeing. I see it also says they are best when the Sun is between 6 and 16 degrees below the horizon. At these latitudes in the early summer, that is going to be after midnight.
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Guest » Wed Jul 20, 2011 6:25 pm

Hey, great! I joined the RASC (Royal Astronomical Society of Canada) in Edmonton in about 1954 or 1955 - with Earl Milton, Franklin Loehde, Ian McLennan, Art Dalton,... It was WONDERFUL, great people! Dick Henry, Professor, Johns Hopkins University, Baltimore

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Wayne Warren » Wed Jul 20, 2011 7:15 pm

The image is a good example of terribly unshielded lights as well as noctilucent clouds. If these lights were adequately shielded, their illumination would be seen only on the ground. Clearly, Edmonton needs a light ordinance.
Wayne Warren/Towson University.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by neufer » Wed Jul 20, 2011 8:15 pm

Wayne Warren wrote:
The image is a good example of terribly unshielded lights as well as noctilucent clouds.
If these lights were adequately shielded, their illumination would be seen only on the ground.
Clearly, Edmonton needs a light ordinance.
The bulk of the light stops within 3 pole heights of each lamp;
I don't see how one could shield it any more in an economic fashion.
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by Chris Peterson » Wed Jul 20, 2011 8:24 pm

neufer wrote:The bulk of the light stops within 3 pole heights of each lamp;
I don't see how one could shield it any more in an economic fashion.
I don't think it is possible to make that determination from this image. However, with a properly shielded light, you should not be able to see the bulb at all from the viewpoint of this shot. The lights should be essentially invisible, except possibly for the poles holding them up.
Chris

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by DavidLeodis » Thu Jul 21, 2011 11:11 am

I am confused as to the date when the image was taken. The "above" link in the explanation brings up a video from which the APOD seems to have been captured. The video is titled 'Noctilucent Cloud over Edmonton, Canada July 1, 2011' and other information with it states it was on Canada Day, which I have found is held on July 1st each year. However, just after the start of the video it gives the date 07 02 2011 (presumably July 2 2011) and at about 5 seconds into the video it states "1 hour (12:11am to 1:15am)". I'm unsure therefore if the event was in the very early hours of July 1st (which was Canada Day) or the very early hours of July 2nd (which was not Canada Day). It is a nice video and APOD picture but spoiled somewhat (at least to me) by the confusing dates. :?

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by neufer » Thu Jul 21, 2011 11:47 am

DavidLeodis wrote:
I am confused as to the date when the image was taken. The "above" link in the explanation brings up a video from which the APOD seems to have been captured. The video is titled 'Noctilucent Cloud over Edmonton, Canada July 1, 2011' and other information with it states it was on Canada Day, which I have found is held on July 1st each year. However, just after the start of the video it gives the date 07 02 2011 (presumably July 2 2011) and at about 5 seconds into the video it states "1 hour (12:11am to 1:15am)". I'm unsure therefore if the event was in the very early hours of July 1st (which was Canada Day) or the very early hours of July 2nd (which was not Canada Day).
It is pretty obviously the celebration night of Canada Day
which runs into July 2.

(It was still Canada Day in Vancouver.)
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by DavidLeodis » Thu Jul 21, 2011 2:11 pm

neufer wrote:
DavidLeodis wrote:
I am confused as to the date when the image was taken. The "above" link in the explanation brings up a video from which the APOD seems to have been captured. The video is titled 'Noctilucent Cloud over Edmonton, Canada July 1, 2011' and other information with it states it was on Canada Day, which I have found is held on July 1st each year. However, just after the start of the video it gives the date 07 02 2011 (presumably July 2 2011) and at about 5 seconds into the video it states "1 hour (12:11am to 1:15am)". I'm unsure therefore if the event was in the very early hours of July 1st (which was Canada Day) or the very early hours of July 2nd (which was not Canada Day).
It is pretty obviously the celebration night of Canada Day
which runs into July 2.

(It was still Canada Day in Vancouver.)
Thanks neufer for your help. I respectfully disagree though, as I don't think "It is pretty obviously the celebration night of Canada Day
which runs into July 2". My feeling was that it probably was taken in the early hours of July 1st and that the July 2nd in the video was a mistake. The dates given with the video are confusing, well they are to me! :)

Edit added around 23:00. Having just read the explanation again I noticed that it states the noctilucent clouds event was "after dusk", so the event cannot have been in the early hours of July 1st and thus the video (which had the APOD image) will have been taken on July 2nd. I'm therefore a bit :oops: not to have picked up on that earlier. As normal then I'm :? but still :) ing.

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by ssreddy555 » Wed Jul 27, 2011 8:47 am

Is it soon after dusk?

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by owlice » Wed Jul 27, 2011 10:24 am

Sunset in Edmonton on July 1 was after 10 PM (10:06 PM). I can easily believe that the NLC were visible past midnight.
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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by gscratch » Tue Sep 06, 2011 8:11 pm

Wayne Warren wrote:The image is a good example of terribly unshielded lights as well as noctilucent clouds. If these lights were adequately shielded, their illumination would be seen only on the ground. Clearly, Edmonton needs a light ordinance.
Wayne Warren/Towson University.
Agreed. Hands down. No contest.

Of course - Edmonton City Management is too busy banning swiss army knives, and cutting back on road maintenance expenditures to focus on lights (even if they are cheaper to operate.)

/Greg

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Re: APOD: Noctilucent Clouds Over Edmonton (2011 Jul 20)

Post by gscratch » Tue Sep 06, 2011 8:12 pm

ssreddy555 wrote:Is it soon after dusk?
The image was taken approximately 3 1/2 hours after sunset. Dusk was effectively over when I began shooting the display at 11:45pm local time.