APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

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Expand view Topic review: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by geckzilla » Tue Dec 23, 2014 4:20 pm

Chris Peterson wrote:
Czerno o wrote:Beautiful composition !
Raises the question : what (process, artifact, aesthetic choice...?) made three sun positions "distinguished" ?
Looks like the imager chose a longer exposure time at those three times. Not sure about the landscape- it could be from one of the long exposures, a composite of the three long exposures, or a composite of even more. The shadows suggest it might have been taken around noon, but it's hard to judge shadows on wide angle shots.
The reflections in the water offer some clues, but I'm not sure either.

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Chris Peterson » Tue Dec 23, 2014 3:31 pm

Czerno o wrote:Beautiful composition !
Raises the question : what (process, artifact, aesthetic choice...?) made three sun positions "distinguished" ?
Looks like the imager chose a longer exposure time at those three times. Not sure about the landscape- it could be from one of the long exposures, a composite of the three long exposures, or a composite of even more. The shadows suggest it might have been taken around noon, but it's hard to judge shadows on wide angle shots.

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Czerno o » Tue Dec 23, 2014 11:16 am

Beautiful composition !
Raises the question : what (process, artifact, aesthetic choice...?) made three sun positions "distinguished" ?

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Czerno o » Tue Dec 23, 2014 11:13 am

Beautiful composition !
Raises the question : what (process, artifact, ...?) made three sun positions "distinguished" - as self evident looking at the picture itself, saves me a description ?

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Nitpicker » Mon Dec 22, 2014 12:16 am

That is a beautiful APOD, thank you. We've officially been enjoying Summer for three weeks already in these parts. And lots of lovely warm weather in October and November, too. Happy Solstice!
Remo wrote:
APOD Robot wrote: So in the north, the solstice day has the shortest length of time between sunrise and sunset and fewest hours of daylight.
Really? You are forgetting the equation of time and the eccentricity of earth's orbit? Notwithstanding that the sun is at the lowest point of declination at the northern winter solstice, the astronomical days are getting longer. This is because earth is approaching perigee in its orbit around the sun. This stretches out both the length of time of daylight and and the length of night, i.e., the time between high noon on Dec 20 to high noon on Dec 21 is a little less than 1/2 second less than the time between high noon on Dec 21 and high noon on Dec 22. In other words, the date of least sunlight can occur prior to the actual solstice.

Since this effect varies with latitude, I ran a hypothetical for San Jose, CA., which indicated that any time the solstice was within 6 hours of the prior day, the prior day would actually have less hours (milliseconds?) of sunlight.
Or maybe one doesn't really have a "pure" solstice day if the exact time of the solstice is too far away from one's local noon? The Sun doesn't care where you live. It just keeps rising and setting on the Earth at all times.

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Remo » Sun Dec 21, 2014 11:11 pm

APOD Robot wrote: So in the north, the solstice day has the shortest length of time between sunrise and sunset and fewest hours of daylight.
Really? You are forgetting the equation of time and the eccentricity of earth's orbit? Notwithstanding that the sun is at the lowest point of declination at the northern winter solstice, the astronomical days are getting longer. This is because earth is approaching perigee in its orbit around the sun. This stretches out both the length of time of daylight and and the length of night, i.e., the time between high noon on Dec 20 to high noon on Dec 21 is a little less than 1/2 second less than the time between high noon on Dec 21 and high noon on Dec 22. In other words, the date of least sunlight can occur prior to the actual solstice.

Since this effect varies with latitude, I ran a hypothetical for San Jose, CA., which indicated that any time the solstice was within 6 hours of the prior day, the prior day would actually have less hours (milliseconds?) of sunlight.

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Chris Peterson » Sun Dec 21, 2014 10:04 pm

Ron-Astro Pharmacist wrote:Wow- I thought the hemispheres seasons were reversed in all aspects. That's why I like this site so much. You can totally mess up and still learn something new. If there ever is a Starship Asterisk* cruise - sign me up. It would be fun to meet those who try to keep me "up to snuff". I'm sure all the moderators would love that idea... :lol2:
I don't suppose you could Cruise to the Atacama anyways :no:
If you had said the December solstice, you would have been correct. But the winter solstice is seasonal. Today is the winter solstice in the northern hemisphere, and the summer solstice in the southern. In six months, the southern hemisphere will experience its winter solstice, and its days will begin to lengthen.

Tricky, huh?

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Ron-Astro Pharmacist » Sun Dec 21, 2014 9:40 pm

Chris Peterson wrote:
Ron-Astro Pharmacist wrote:
Chris Peterson wrote:I always love the Winter Solstice. Sunset on another year but the Sunrise of longer days. At least for us Northerners The winter solstice always marks the beginning of longer days. This is as true in the northern hemisphere as in the southern.
Wow- I thought the hemispheres seasons were reversed in all aspects. That's why I like this site so much. You can totally mess up and still learn something new. If there ever is a Starship Asterisk* cruise - sign me up. It would be fun to meet those who try to keep me "up to snuff". I'm sure all the moderators would love that idea... :lol2:
I don't suppose you could Cruise to the Atacama anyways :no:

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Chris Peterson » Sun Dec 21, 2014 5:33 pm

Ron-Astro Pharmacist wrote:
Chris Peterson wrote:
Ron-Astro Pharmacist wrote:I always love the Winter Solstice. Sunset on another year but the Sunrise of longer days. At least for us Northerners!! :P
And for Southerners, too, (except for the new year) if you consider carefully what you wrote!
Yea - you get one chance to get it right. They (and we) get the sunrise of a new year but the sunset of longer days. One of these new years I want to experience it from their perspective. I can't wait to see our common constellations without standing on my head. :D
Nope, you're still missing it. The winter solstice always marks the beginning of longer days. This is as true in the northern hemisphere as in the southern.

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Ron-Astro Pharmacist » Sun Dec 21, 2014 5:30 pm

Chris Peterson wrote:
Ron-Astro Pharmacist wrote:I always love the Winter Solstice. Sunset on another year but the Sunrise of longer days. At least for us Northerners!! :P
And for Southerners, too, (except for the new year) if you consider carefully what you wrote!
Yea - you get one chance to get it right. They (and we) get the sunrise of a new year but the sunset of longer days. One of these new years I want to experience it from their perspective. I can't wait to see our common constellations without standing on my head. :D

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Chris Peterson » Sun Dec 21, 2014 4:59 pm

Ron-Astro Pharmacist wrote:I always love the Winter Solstice. Sunset on another year but the Sunrise of longer days. At least for us Northerners!! :P
And for Southerners, too, (except for the new year) if you consider carefully what you wrote!

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Ron-Astro Pharmacist » Sun Dec 21, 2014 4:03 pm

I always love the Winter Solstice. Sunset on another year but the Sunrise of longer days. At least for us Northerners!! :P

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by Boomer12k » Sun Dec 21, 2014 3:22 pm

Happy Solstice Day....Did you get me a present????? :lol2:

Wonderful Pic...

Time to change to a WINTER wallpaper.
:---[===] *

Re: APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by BDanielMayfield » Sun Dec 21, 2014 2:44 pm

Awesome photo. :clap: :clap:

APOD: Tyrrhenian Sea and Solstice Sky (2014 Dec 21)

by APOD Robot » Sun Dec 21, 2014 5:06 am

Image Tyrrhenian Sea and Solstice Sky

Explanation: Today the solstice occurs at 23:03 Universal Time, the Sun reaching its southernmost declination in planet Earth's sky. Of course, the December solstice marks the beginning of winter in the northern hemisphere and summer in the south. When viewed from northern latitudes, and as shown in the above horizontally compressed image, the Sun will make its lowest arc through the sky along the southern horizon. So in the north, the solstice day has the shortest length of time between sunrise and sunset and fewest hours of daylight. This striking composite image follows the Sun's path through the December solstice day of 2005 in a beautiful blue sky, looking down the Tyrrhenian Sea coast from Santa Severa toward Fiumicino, Italy. The view covers about 115 degrees in 43 separate, well-planned exposures from sunrise to sunset.

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