APOD: Tyrrhenian Sea and Solstice Sky (2010 Dec 21)

[APOD Robot]

Tyrrhenian Sea and Solstice Sky

Explanation: Today the solstice occurs at 23:38 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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[neufer]

Olive tree, Japanese Maple, Larch,...

[Ron]

Just for the record, the season of summer in Australia is generally quoted as beginning at the start of December, not the Summer Solstice.

All the other seasons begin at months beginning too.

Perhaps someone could could quote the historical reasoning behind this ?
It does seem to provide a fair correlation with the seasons.....

Marvellously illustrative picture of the skyward passage of the sun here.
(why do only 3 sun images flare ?).

[Chris Peterson]

Just for the record, the season of summer in Australia is generally quoted as beginning at the start of December, not the Summer Solstice.

It's pretty arbitrary when a "season" actually begins. Different countries have different civil definitions. In many cases, I guess there's no official date at all, just custom and convention.

Solstices logically mark what might be considered the middle of a season, but seasonal weather extremes typically lag the solstices by two to six weeks, depending on latitude.

[orin stepanek]

To me Winter and Summer are the longest seasons; while Spring and Fall are the shortest. I wish it were the opposite. The Solstice makes a good marking point for Winter and Summer though. I wonder if they even consider a Winter season in places along the Equator.

[Redbone]

Great picture (composite), soltices are my favorite times of the year. The shortening/lengthening of the days comes to a complete stop, at least for an instant, time to take a rest from the relentless sway of the seasons.

In central America, the seasons are commonly defined by rain. The dry season is considered summer, say September through March, the wet season is called winter.

[neufer]

Click to play embedded YouTube video.

Leonardo da Vinci made many unsuccessful attempts to design a flying machine based on the principle of flapping flight with a flexible wing. This design, one of the his earliest, consisted of a wooden framework and two movable wings. The aviator was to lie prone in the framework and work the wings by pulleys connected with stirrups moved with his feet, aided by a windlass worked with his hands and arms. In later designs, often with more than single pair of wings, Leonardo had the operator standing upright.

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Tyrrhenian Sea and Solstice Sky

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.

<<Leonardo da Vinci-Fiumicino Airport (Aeroporto Leonardo da Vinci di Fiumicino), commonly known as Fiumicino Airport, is Italy's largest airport with 33,811,637 passengers served, located in Fiumicino, 35 km from Rome's historic city centre.>>

[img3="Leonardo da Vinci was fascinated with the form of the spiral. His helicopter takes the form of an aerial screw, following the example of a device earlier brought to Europe from Asia in the form of a children's toy. He wrote of his design for the helicopter: "If this instrument made with a screw be well made — that is to say, made with linen of which the pores are stopped up with starch — and be turned swiftly, the said screw will make its spiral in the air and it will rise up high.""]http://www-03.ibm.com/ibm/history/exhib ... es/174.jpg[/img3]

[lenka]

good picture - good news. More sun shine finally!

[biddie67]

Great job! This is both an informative and beautiful picture!! I'm happy to see that the days will be getting longer now - short days and long nights are not my favorite time of the year.

[bystander]

APOD: Tyrrhenian Sea and Solstice Sky (2007 Dec 22)
http://asterisk.apod.com/vie ... =9&t=13028

[Landy]

Just for the record, the season of summer in Australia is generally quoted as beginning at the start of December, not the Summer Solstice.

All the other seasons begin at months beginning too.

Perhaps someone could could quote the historical reasoning behind this ?
It does seem to provide a fair correlation with the seasons.....

Marvellously illustrative picture of the skyward passage of the sun here.
(why do only 3 sun images flare ?).

Perhaps that's the way the months of the calendar were originally set up? I am also in Australia, and ever since I was a nerdy kid reading astronomy books, it never made any sense to me why the astronomical definition of the beginning of seasons were set at the solstices/equinoxes. If you think about it astronomically, summer should be defined as that quarter of the year where the hemisphere you are in receives the greatest amount of insolation. The summer solstice (which is today here - 22nd Dec) should mark the precise middle of summer - not the start of it! This argument is put forward very elegantly by Phil Plait on his "Bad Astronomy" website http://www.badastronomy.com/bad/misc/badseasons.html.

Therefore the more correct astronomical definition of when the seasons begin is some six weeks before the solstices/equinoxes. For the southern hemisphere summer (northern hemisphere winter), that would be the 7th of November, which could also be called "Beltaine" (or "Samhain" for the northerners) - see http://www.archaeoastronomy.com/2010.html. By the way that site is a very useful resource for the timing of these events.

However, speaking meteorologically, it takes a few weeks for weather systems, atmospheric temperatures etc to respond to changing insolation, and so the beginning of December marks the beginning of that quarter of the year which has the ~90 warmest days (on average). So from a human/geographical perspective, the start of the seasons is best marked by the 1st of the month.
Hope this makes sense!

And I agree - it is an excellent picture. Not sure about the flaring thing, but i suspect the photographer put a flaring filter on the camera for those three exposures.

[bystander]

More sun shine finally!

or less, if you happen to be down under.

[owlice]

Meteorological

Meteorological seasons are reckoned by temperature, with summer being the hottest quarter of the year and winter the coldest quarter of the year. Using this reckoning, the Roman calendar began the year and the spring season on the first of March, with each season occupying three months. In 1780 the Societas Meteorologica Palatina, an early international organization for meteorology, defined seasons as groupings of three whole months. Ever since, professional meteorologists all over the world have used this definition.[5] Therefore, in meteorology for the Northern hemisphere, spring begins on 1 March, summer on 1 June, autumn on 1 September, and winter on 1 December.

That from here: http://en.wikipedia.org/wiki/Season#Meteorological

The local weather guys talk about this (different definitions of "season") regularly.

[orin stepanek]

Winter is definately here! Spring is 3 months away; Autumn is over and Summer is a distant memory But here is the Four Seasons I liked so well!!

Click to play embedded YouTube video.

[mexhunter]

Congratulations to Danilo, Is a beautiful picture We have here.
Greetings
César

[Rink]

A very nice photo. Look at the shadows of the stones in the lower left quadrant. How did the photographer arrange to have the shadows recorded from only one of the exposures?

[DavidLeodis]

It is a good image but I prefer the non-compressed version that is brought up through the 'This striking composite' link. There did not seem to be any need to horiziontally compress the image, as the non-compressed one is not that much wider.