Winter Solstice

Literiding
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Winter Solstice

Postby Literiding » Thu Dec 21, 2017 9:06 pm

For those of us who live outside a lot, today is an important day, it is the shortest day of the year and the longest night of the year. From this point onward, even though the days may be cold, the amount of daylight will increase each day. The actual length of the day and night are determined by the observers latitude. At the "Tropic of Capricorn" the sun is directly overhead at the "local apparent noon" and the sun never rose above the horizon when at or north of the northern arctic circle.

There are all sorts of celebrations dating back to prehistoric times to mark the shortest day of the year. The early Catholic Church usurped the pagan winter festivals to celebrate the Nativity. The actual season of the Nativity was sometime in the fall in about the the year 3 or 4 BC.

Moutaineer
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Re: Winter Solstice

Postby Moutaineer » Thu Dec 21, 2017 9:28 pm

And, right on schedule, my water trough had a thin coating of blown white hair this morning!

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Re: Winter Solstice

Postby Amado » Fri Dec 22, 2017 10:33 am

I have been looking forward to this day. I always feel better when the days start getting longer. Though up here, the forecast gets so much colder! This is next week. Our son comes to visit from Seattle on Wednesday. Hope he has warm clothes!

Image

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Re: Winter Solstice

Postby highoctane » Fri Dec 22, 2017 4:23 pm

Yesterday was my favorite day of the year, every year. I'm "solar powered", so I get my energy/self esteem/gumption to do anything at all from Vitamin D. :-D

PaulaO
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Re: Winter Solstice

Postby PaulaO » Fri Dec 22, 2017 5:59 pm

There is an old saying "as the days begin to lengthen, the cold begins to strengthen." I hope that is not true!

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Re: Winter Solstice

Postby Tarlo Farm » Mon Dec 25, 2017 5:53 pm

PaulaO wrote:There is an old saying "as the days begin to lengthen, the cold begins to strengthen." I hope that is not true!



"Thermal Lag" It's why the hottest days are in July and August, not June. As to the rest of it, patience Grasshoppers. Pay special attention to number three and four:

https://www.washingtonpost.com/news/cap ... 59669f2d36

Literiding
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Re: Winter Solstice

Postby Literiding » Tue Dec 26, 2017 11:57 am

Tarlo Farm wrote:"Thermal Lag" It's why the hottest days are in July and August, not June. As to the rest of it, patience Grasshoppers. Pay special attention to number three and four:

https://www.washingtonpost.com/news/cap ... 59669f2d36


Ok, and do you know why the sun continues to set later and rise later until about January 8th, even though the interval between sun set and sun rise is getting shorter?

It is because of the sun's "analemma." If you enter "analemma" in your internet search engine, and view the resultant images, you'll see why.

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Re: Winter Solstice

Postby Tarlo Farm » Wed Dec 27, 2017 6:05 pm


Literiding
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Re: Winter Solstice

Postby Literiding » Mon Jan 01, 2018 2:40 pm

When I went out to feed this morning before sunrise, there was a grand and rare sight in the sky, four planets lined up in a row. The best illustration that I could find online was for Australia so it is a mirror image of what I saw:

extra_large-bright-planets-come-together-in-the-morning-sky.jpg
extra_large-bright-planets-come-together-in-the-morning-sky.jpg (10.3 KiB) Viewed 9859 times


In the northern hemisphere, the planets start in the lower left hand corner and sweep up to the upper right hand.

Tarlo Farm
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Re: Winter Solstice

Postby Tarlo Farm » Mon Jan 01, 2018 3:14 pm

Well, I just spent a half hour thoroughly reading and trying to understand that Wiki article. I got about 80% of it (the calculations and symbols throw me), very cool and I think I can explain it well enough to my non-science friends.
It reminded me of the first time I went to Jamaica in March from Michigan, anticipating lengthy warm days. Imagine my initial surprise when the sun set - and rose - at about 6:30. Duh! It WAS warm though. :lol: :lol:

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Re: Winter Solstice

Postby PaulaO » Mon Jan 01, 2018 4:46 pm

Literiding, that is a cool picture.

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Re: Winter Solstice

Postby kande50 » Mon Jan 01, 2018 8:05 pm

Tarlo Farm wrote:It reminded me of the first time I went to Jamaica in March from Michigan, anticipating lengthy warm days. Imagine my initial surprise when the sun set - and rose - at about 6:30. Duh! It WAS warm though. :lol: :lol:


When I discovered that about Florida I couldn't imagine why anyone would want to move down there--although I'm starting to get it now that my energy levels are tanking. :-)

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Re: Winter Solstice

Postby Literiding » Mon Jan 15, 2018 3:47 pm

From the National Weather Service at Wakefield, VA, here are the sunrise and sunset times. As you inspect the table, you can see how the day has reached it’s shortest length on Dec 21st, but sun rise and sunset continue to get later and later because of the sun’s analemma:

winter-analemma.jpg
winter-analemma.jpg (99.77 KiB) Viewed 9770 times


SUNRISE AND SUNSET TIME EASTERN STANDARD TIME WITH THE LENGHT OF DAY IN HOURS AND MINUTES
Time shown here are to the nearest minute so changes in seconds aren’t always shown

DECEMBER 13 2017......SUNRISE...709 AM EST...SUNSET...449 PM EST...DAY LENGTH 9 HR 40 MIN
DECEMBER 14 2017......SUNRISE...710 AM EST...SUNSET...449 PM EST...DAY LENGTH 9 HR 39 MIN
DECEMBER 15 2017......SUNRISE...711 AM EST...SUNSET...450 PM EST...DAY LENGTH 9 HR 39 MIN
DECEMBER 16 2017......SUNRISE...711 AM EST...SUNSET...450 PM EST...DAY LENGTH 9 HR 39 MIN
DECEMBER 17 2017......SUNRISE...712 AM EST...SUNSET...450 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 18 2017......SUNRISE...712 AM EST...SUNSET...451 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 19 2017......SUNRISE...713 AM EST...SUNSET...451 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 20 2017......SUNRISE...714 AM EST...SUNSET...452 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 21 2017......SUNRISE...714 AM EST...SUNSET...452 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 22 2017......SUNRISE...715 AM EST...SUNSET...453 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 23 2017......SUNRISE...715 AM EST...SUNSET...453 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 24 2017......SUNRISE...716 AM EST...SUNSET...454 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 25 2017......SUNRISE...716 AM EST...SUNSET...454 PM EST...DAY LENGTH 9 HR 38 MIN
DECEMBER 26 2017......SUNRISE...716 AM EST...SUNSET...455 PM EST...DAY LENGTH 9 HR 39 MIN
DECEMBER 27 2017......SUNRISE...717 AM EST...SUNSET...456 PM EST...DAY LENGTH 9 HR 39 MIN
DECEMBER 28 2017......SUNRISE...717 AM EST...SUNSET...456 PM EST...DAY LENGTH 9 HR 39 MIN
DECEMBER 29 2017......SUNRISE...717 AM EST...SUNSET...457 PM EST...DAY LENGTH 9 HR 40 MIN
DECEMBER 30 2017......SUNRISE...717 AM EST...SUNSET...458 PM EST...DAY LENGTH 9 HR 41 MIN
DECEMBER 31 2017......SUNRISE...718 AM EST...SUNSET...458 PM EST...DAY LENGTH 9 HR 40 MIN
JANUARY__ 1 2018......SUNRISE...718 AM EST...SUNSET...459 PM EST...DAY LENGTH 9 HR 41 MIN
JANUARY__ 2 2018......SUNRISE...718 AM EST...SUNSET...500 PM EST...DAY LENGTH 9 HR 42 MIN
JANUARY__ 3 2018......SUNRISE...718 AM EST...SUNSET...501 PM EST...DAY LENGTH 9 HR 43 MIN
JANUARY__ 4 2018......SUNRISE...718 AM EST...SUNSET...502 PM EST...DAY LENGTH 9 HR 44 MIN
JANUARY__ 5 2018......SUNRISE...718 AM EST...SUNSET...503 PM EST...DAY LENGTH 9 HR 45 MIN
JANUARY__ 6 2018......SUNRISE...718 AM EST...SUNSET...503 PM EST...DAY LENGTH 9 HR 45 MIN
JANUARY__ 7 2018......SUNRISE...718 AM EST...SUNSET...504 PM EST...DAY LENGTH 9 HR 46 MIN
JANUARY__ 8 2018......SUNRISE...718 AM EST...SUNSET...505 PM EST...DAY LENGTH 9 HR 47 MIN
JANUARY__ 9 2018......SUNRISE...718 AM EST...SUNSET...506 PM EST...DAY LENGTH 9 HR 48 MIN
JANUARY_ 10 2018......SUNRISE...718 AM EST...SUNSET...507 PM EST...DAY LENGTH 9 HR 49 MIN
JANUARY_ 11 2018......SUNRISE...718 AM EST...SUNSET...508 PM EST...DAY LENGTH 9 HR 50 MIN
JANUARY_ 12 2018......SUNRISE...718 AM EST...SUNSET...509 PM EST...DAY LENGTH 9 HR 51 MIN
JANUARY_ 13 2018......SUNRISE...717 AM EST...SUNSET...510 PM EST...DAY LENGHT 9 HR 53 MIN
JANUARY_ 14 2018......SUNRISE...717 AM EST...SUNSET...511 PM EST...DAY LENGHT 9 HR 54 MIN
JANUARY_ 15 2018......SUNRISE...717 AM EST...SUNSET...512 PM EST...DAY LENGTH 9 HR 55 MIN
JANUARY_ 16 2018......SUNRISE...716 AM EST...SUNSET...513 PM EST...DAY LENGTH 9 HR 57 MIN

So why did anyone care about the analemma, because it is one of the forest of corrections needed to determine what time it is exactly. Up to the 1960’s, the rotation of the earth was the most precise standard of time keeping until the invention of the atomic clock. The rotation of the earth was measured by when a star transited the center of field of a Meridian Circle at the observers location.

https://en.wikipedia.org/wiki/Meridian_circle

Because the mathematics involved are an equation, if you know the location, you can determine the time exactly. Conversely, if you know the time exactly, you can determine the observer’s location exactly. But this leads to a “chicken or the egg” conundrum which was solved in 1884 when the Royal Observatory, Greenwich, England, became the international reference for determining time.

https://en.wikipedia.org/wiki/Royal_Obs ... _Greenwich

So with the development of the chronometer, a navigator could take his time standard and determine his location on the oceans (also on land as well):

https://en.wikipedia.org/wiki/Marine_chronometer

This is how I became familiar with the subject, I’m old enough that twice, I was the Navigator of a U.S. warship and my responsibilities included determining the ship’s position via celestial navigation. The development of GPS was still a top secret project at DARPA. I did work with an early predecessor of GPS, call TRANSIT which would give a fix (your location and time) about once every four hours.


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