APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Comments and questions about the APOD on the main view screen.
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APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by APOD Robot » Tue Dec 22, 2015 5:14 am

Image Solstice Illuminated: A Year of Sky

Explanation: Can you find which day is the winter solstice? Each panel shows one day. With 360 movie panels, the sky over (almost) an entire year is shown in time lapse format as recorded by a video camera on the roof of the Exploratorium museum in San Francisco, California. The camera recorded an image every 10 seconds from before sunrise to after sunset and from mid-2009 to mid-2010. A time stamp showing the local time of day is provided on the lower right. The videos are arranged chronologically, with July 28 shown on the upper left, and January 1 located about half way down. In the videos, darkness indicates night, blue depicts clear day, while gray portrays pervasive daytime cloud cover. Many videos show complex patterns of clouds moving across the camera's wide field as that day progresses. The initial darkness in the middle depicts the delayed dawn and fewer daylight hours of winter. Although every day lasts 24 hours, nighttime lasts longest in the northern hemisphere in December and the surrounding winter months. Therefore, finding the panel with the longest night will locate the day of winter solstice -- which happens to be today in the northern hemisphere. As the videos collectively end, sunset and then darkness descend first on the winter days just above the middle, and last on the mid-summer near the bottom.

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by Boomer12k » Tue Dec 22, 2015 5:17 am

Way too confusing....I am NOT a fly....

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by Beyond » Tue Dec 22, 2015 5:42 am

Too monotonous for me.
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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by BMAONE23 » Tue Dec 22, 2015 5:52 am

I count 28 days with rain and 112-125 gray days

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by Ann » Tue Dec 22, 2015 6:33 am

Interesting! If we assume that the video starts in January, then February, March and April appear to be the clearest, less cloudy months. In Sweden, April is often the least cloudy as well as the driest month. But in June, the month of my birthday, the rain often starts pouring down!

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by alter-ego » Tue Dec 22, 2015 6:43 am

By eye-balling the collection to estimate the solstice from the latest sunrise and earliest sunset days, and then finding the actual solstice day (assuming 7/28/09 is at the upper left), my estimate missed by about 8 days.
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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by RedFishBlueFish » Tue Dec 22, 2015 10:11 am

Fascinating. Have it looping full screen on a third monitor.

For a one-off viewing though, it would be more effective had Mies's aphorism been kept less far afield.

ianmr

Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by ianmr » Tue Dec 22, 2015 12:09 pm

If a snapshot was taken every ten seconds, why was there so much activity in each on a second by secon basis?

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by TJB » Tue Dec 22, 2015 1:00 pm

According to http://www.archaeoastronomy.com/2015.html the 2015 Winter Solstice in the Northern Hemisphere occurred at 04:48 UT on 22 Dec. 2015, which means that in the Eastern Time Zone, it occurred at 23:48 on 21 Dec., and one hour earlier in each time zone to the west, to the International Date Line. So for the entire US, this year's Winter Solstice was yesterday, 21 Dec.

BobB

Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by BobB » Tue Dec 22, 2015 3:10 pm

Interesting. Did anyone else see the silhouettes of people flash across the image of October 10, at 10:10am?

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by geckzilla » Tue Dec 22, 2015 3:35 pm

ianmr wrote:If a snapshot was taken every ten seconds, why was there so much activity in each on a second by secon basis?
Because each snapshot is replayed back within milliseconds of each other? The website states 24 frames per second. http://www.murphlab.com/hsky/
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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by jasonhc73@yahoo.com » Tue Dec 22, 2015 5:40 pm

I wish it would have been able to see something more in the sky. For example like more contrails in the sky, that would be neat to see a scheduled flight across several days.

Fascinating none the less. Very interesting to see the day wake up and then go to bed throughout the entire year, all at once.

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by jasonhc73@yahoo.com » Tue Dec 22, 2015 5:48 pm

jasonhc73@yahoo.com wrote:I wish it would have been able to see something more in the sky. For example like more contrails in the sky, that would be neat to see a scheduled flight across several days.

Fascinating none the less. Very interesting to see the day wake up and then go to bed throughout the entire year, all at once.
Thought I saw the moon go by in one of them... I think it was just a cloud though.

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by MarkBour » Tue Dec 22, 2015 6:48 pm

Ann wrote:Interesting! If we assume that the video starts in January, ...
Ann, as the caption says: "with July 28 shown on the upper left, and January 1 located about half way down."
Just eyeballing it, it therefore feels like Sep, Oct, Nov, May and Jun were the clearest months from this spot.
BobB wrote:Interesting. Did anyone else see the silhouettes of people flash across the image of October 10, at 10:10am?
Yes! Although I did not figure out the exact day, like you did. That was nice. Some also show up from 2-3pm on the same day. I wonder if it was a day a special tour of the roof was offered?

If I'm not mistaken, the clouds move by faster at the top and bottom of the collage. This would mean that clouds are moving by faster in the months of Jun-Aug than in the middle of winter. Which is the opposite of what I would have expected.
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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by Ann » Tue Dec 22, 2015 7:04 pm

MarkBour wrote:
Ann wrote:Interesting! If we assume that the video starts in January, ...
Ann, as the caption says: "with July 28 shown on the upper left, and January 1 located about half way down."
Just eyeballing it, it therefore feels like Sep, Oct, Nov, May and Jun were the clearest months from this spot.
Thanks! Oh, October and November are clear months in San Fransisco? Wish that was the case here! We hardly see any blue sky at all here in November and December. And not much of it in January and February either. Leonids, Geminids and other fall meteor showers round here? I don't think so. :evil:

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by MarkBour » Tue Dec 22, 2015 9:26 pm

Ann wrote:We hardly see any blue sky at all here in November and December. And not much of it in January and February either. Leonids, Geminids and other fall meteor showers round here? I don't think so. :evil:
Ann
We usually have better viewing, but this year, I think, has been awful. I'm betting it was the most overcast year in the the last twenty! (Illinois, USA). It has felt as gloomy as London. I hope it's random ... not a climate change effect. However, I see a NASA article (if I'm not reading too much into it) indicating that global warming implies greater cloud cover. An effect I would fully expect.
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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by Tszabeau » Wed Dec 23, 2015 1:07 am

I find this utterly facsinating visually and conceptually.

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Re: APOD: Solstice Illuminated: A Year of Sky (2015 Dec 22)

Post by islander2 » Wed Dec 23, 2015 4:52 am

I have returned

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Sunrise and Sunset colors

Post by SciGuy » Mon Dec 28, 2015 7:00 pm

I notice the sunrises and sunsets are much more colorful in the late summer/fall months (the top several rows of this composite), rather than in the spring/early summer months. Does anyone have a scientific explanation for this? It is not due to changing the camera angle, since it must be facing north in all the videos as we never see the sun directly. And it is not due to cloud cover, since there appear to be many days in the spring with high scattered clouds that could reflect a colorful sky.

So, any ideas?

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Re: Sunrise and Sunset colors

Post by Chris Peterson » Mon Dec 28, 2015 7:05 pm

SciGuy wrote:I notice the sunrises and sunsets are much more colorful in the late summer/fall months (the top several rows of this composite), rather than in the spring/early summer months. Does anyone have a scientific explanation for this? It is not due to changing the camera angle, since it must be facing north in all the videos as we never see the sun directly. And it is not due to cloud cover, since there appear to be many days in the spring with high scattered clouds that could reflect a colorful sky.

So, any ideas?
Well, late summer and fall are the peak of the wildfire season in the western U.S., which means the atmosphere is full of smoke, and that produces colorful sunrises and sunsets.
Chris

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