Where can the sun cross on only one day a year?

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Where can the sun cross on only one day a year?

Moongazer
Hello Calendar people,
 
I saw a re-broadcast last night of an Al-Jazeera news bulletin, in which one item piqued my interest. Some of the details might be slightly inaccurate, but this was the gist of it:  A memorial is being set up somewhere in Chile to commemorate attacks on the Mapuche people, an indigenous minority, during the years of the brutal Pinochet government. It is located on a site traditionally sacred to them because (and this is the part that piqued my interest), at that place, "on only one day a year, the sun's rays pass directly from one side to the other."

That last bit had me puzzled. I reasoned that it must be related to the Sun's north-south movement, but why on only one day a year? Shouldn't it be twice a year - once on the way south and then again on the way back north? So I thought that maybe the place is just a tiny bit north of the Tropic of Capricorn, so that, on the day of the summer solstice, the Sun crosses that place headng south and then crosses back again overnight.
 
However there is a problem with that theory: At the time of the solstices, the Sun's north-south movement seems to slow down quite a bit, so that between crossing over such a place heading southhward and crossing back over again heading northward, it would probably take at least 24 hours and possibly longer.
 
Any thoughts? In particular, did anyone else see that news item and catch the location?
 
Moongazer.
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Re: Where can the sun cross on only one day a year?

Victor Engel
Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.


By the way, the Tropic of Capricorn is constantly moving.

Victor

On Sun, Jan 7, 2018 at 5:04 PM, Moongazer <[hidden email]> wrote:
Hello Calendar people,
 
I saw a re-broadcast last night of an Al-Jazeera news bulletin, in which one item piqued my interest. Some of the details might be slightly inaccurate, but this was the gist of it:  A memorial is being set up somewhere in Chile to commemorate attacks on the Mapuche people, an indigenous minority, during the years of the brutal Pinochet government. It is located on a site traditionally sacred to them because (and this is the part that piqued my interest), at that place, "on only one day a year, the sun's rays pass directly from one side to the other."

That last bit had me puzzled. I reasoned that it must be related to the Sun's north-south movement, but why on only one day a year? Shouldn't it be twice a year - once on the way south and then again on the way back north? So I thought that maybe the place is just a tiny bit north of the Tropic of Capricorn, so that, on the day of the summer solstice, the Sun crosses that place headng south and then crosses back again overnight.
 
However there is a problem with that theory: At the time of the solstices, the Sun's north-south movement seems to slow down quite a bit, so that between crossing over such a place heading southhward and crossing back over again heading northward, it would probably take at least 24 hours and possibly longer.
 
Any thoughts? In particular, did anyone else see that news item and catch the location?
 
Moongazer.

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Re: Where can the sun cross on only one day a year?

Moongazer
Hi Victor and calendar people,
 
That Al-Jazeera report is now on YouTube here:  https://www.youtube.com/watch?v=r6rTTTEEBfM  where, if you pause it at 1:05, you can see that the place that the reporter, Lucia Newman, is at is Temuco, an historical stronghold of the Mapuches, where the site of the memorial will be located. Temuco's coordinates are: 38.7359° S, 72.5904° W. So the Sun's crossing "from one side to the other" is not related to its north-south movement at all. So it seems a complete mystery what that crossing is about and why it only occurs on one day in the year.
 
As for Victor's remarks about Veterans Day, in England and Australia it is called Armistice Day or Remembrance Day, and the Shrine of Remembrance in Melbourne contains a skylight through which the Sun's rays illuminate an inscription at 11:00 on that day each year. (See: https://en.wikipedia.org/wiki/Shrine_of_Remembrance#Architecture_and_features ) It was built before Daylight Saving Time was introduced in Victoria and nowadays a mirror adjusts for DST. I guess if the opening is large enough, the effect is the same regardless of calendar jitter, or maybe there are exceptions in some years when it doesn't work.
 
Moongazer
 

From: "Victor Engel" <[hidden email]>Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.
 
 
By the way, the Tropic of Capricorn is constantly moving.
 
Victor
 
 
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Re: Where can the sun cross on only one day a year?

Victor Engel
I gather it works this way: the sun's rays travel from the sun to Earth. At the earth end, the rays traverse the memorial site, probably at dawn (could also be sunset). I agree there should be two times a year, unless the time is a solstice. The problem with the solstices, though, is tgat the sun's movement is most stationary then, thus reducing the precision of what day the phenomenon occurs.

Victor

On Mon, Jan 8, 2018 at 2:51 AM Moongazer <[hidden email]> wrote:


Hi Victor and calendar people,




 




That Al-Jazeera report is now on YouTube here:  https://www.youtube.com/watch?v=r6rTTTEEBfM  where, if you pause it at 1:05, you can see that the place that the reporter, Lucia Newman, is at is Temuco, an historical stronghold of the Mapuches, where the site of the memorial will be located. Temuco's coordinates are: 38.7359° S, 72.5904° W. So the Sun's crossing "from one side to the other" is not related to its north-south movement at all. So it seems a complete mystery what that crossing is about and why it only occurs on one day in the year.




 




As for Victor's remarks about Veterans Day, in England and Australia it is called Armistice Day or Remembrance Day, and the Shrine of Remembrance in Melbourne contains a skylight through which the Sun's rays illuminate an inscription at 11:00 on that day each year. (See: https://en.wikipedia.org/wiki/Shrine_of_Remembrance#Architecture_and_features ) It was built before Daylight Saving Time was introduced in Victoria and nowadays a mirror adjusts for DST. I guess if the opening is large enough, the effect is the same regardless of calendar jitter, or maybe there are exceptions in some years when it doesn't work.




 




Moongazer




 






From: "Victor Engel" <[hidden email]>Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.



 








 




By the way, the Tropic of Capricorn is constantly moving.




 




Victor


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Re: Where can the sun cross on only one day a year?

Amos Shapir-2
Hi Moongazer and calendar people,

Because of the Sun's analemma, the Sun's position in the sky (azimuth & elevation) at noon -- or at any other specific time of day -- happens at a different place each day of the year, except the longitudinal equinoxes, when the two branches of the figure-8 meet.

Thus it is possible to build a pole or skylight which directs shadow/sunlight to a specific point exactly once a year at a specific hour.

Virus-free. www.avg.com

On Mon, Jan 8, 2018 at 4:48 PM, Victor Engel <[hidden email]> wrote:
I gather it works this way: the sun's rays travel from the sun to Earth. At the earth end, the rays traverse the memorial site, probably at dawn (could also be sunset). I agree there should be two times a year, unless the time is a solstice. The problem with the solstices, though, is tgat the sun's movement is most stationary then, thus reducing the precision of what day the phenomenon occurs.

Victor

On Mon, Jan 8, 2018 at 2:51 AM Moongazer <[hidden email]> wrote:


Hi Victor and calendar people,




 




That Al-Jazeera report is now on YouTube here:  https://www.youtube.com/watch?v=r6rTTTEEBfM  where, if you pause it at 1:05, you can see that the place that the reporter, Lucia Newman, is at is Temuco, an historical stronghold of the Mapuches, where the site of the memorial will be located. Temuco's coordinates are: 38.7359° S, 72.5904° W. So the Sun's crossing "from one side to the other" is not related to its north-south movement at all. So it seems a complete mystery what that crossing is about and why it only occurs on one day in the year.




 




As for Victor's remarks about Veterans Day, in England and Australia it is called Armistice Day or Remembrance Day, and the Shrine of Remembrance in Melbourne contains a skylight through which the Sun's rays illuminate an inscription at 11:00 on that day each year. (See: https://en.wikipedia.org/wiki/Shrine_of_Remembrance#Architecture_and_features ) It was built before Daylight Saving Time was introduced in Victoria and nowadays a mirror adjusts for DST. I guess if the opening is large enough, the effect is the same regardless of calendar jitter, or maybe there are exceptions in some years when it doesn't work.




 




Moongazer




 






From: "Victor Engel" <[hidden email]>Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.



 








 




By the way, the Tropic of Capricorn is constantly moving.




 




Victor





--
Amos Shapir
 
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Re: Where can the sun cross on only one day a year?

Victor Engel
Dear Amos, Moongazer, and Calendar People,

Key additional phrase there is "at a specific hour". If the situation is as I speculated, e.g., sunrise, the same location of the rising sun would be at different times except at the intersection of the analemma for non-solstice dates.

Victor

On Mon, Jan 8, 2018 at 9:57 AM, Amos Shapir <[hidden email]> wrote:
Hi Moongazer and calendar people,

Because of the Sun's analemma, the Sun's position in the sky (azimuth & elevation) at noon -- or at any other specific time of day -- happens at a different place each day of the year, except the longitudinal equinoxes, when the two branches of the figure-8 meet.

Thus it is possible to build a pole or skylight which directs shadow/sunlight to a specific point exactly once a year at a specific hour.

Virus-free. www.avg.com

On Mon, Jan 8, 2018 at 4:48 PM, Victor Engel <[hidden email]> wrote:
I gather it works this way: the sun's rays travel from the sun to Earth. At the earth end, the rays traverse the memorial site, probably at dawn (could also be sunset). I agree there should be two times a year, unless the time is a solstice. The problem with the solstices, though, is tgat the sun's movement is most stationary then, thus reducing the precision of what day the phenomenon occurs.

Victor

On Mon, Jan 8, 2018 at 2:51 AM Moongazer <[hidden email]> wrote:


Hi Victor and calendar people,




 




That Al-Jazeera report is now on YouTube here:  https://www.youtube.com/watch?v=r6rTTTEEBfM  where, if you pause it at 1:05, you can see that the place that the reporter, Lucia Newman, is at is Temuco, an historical stronghold of the Mapuches, where the site of the memorial will be located. Temuco's coordinates are: 38.7359° S, 72.5904° W. So the Sun's crossing "from one side to the other" is not related to its north-south movement at all. So it seems a complete mystery what that crossing is about and why it only occurs on one day in the year.




 




As for Victor's remarks about Veterans Day, in England and Australia it is called Armistice Day or Remembrance Day, and the Shrine of Remembrance in Melbourne contains a skylight through which the Sun's rays illuminate an inscription at 11:00 on that day each year. (See: https://en.wikipedia.org/wiki/Shrine_of_Remembrance#Architecture_and_features ) It was built before Daylight Saving Time was introduced in Victoria and nowadays a mirror adjusts for DST. I guess if the opening is large enough, the effect is the same regardless of calendar jitter, or maybe there are exceptions in some years when it doesn't work.




 




Moongazer




 






From: "Victor Engel" <[hidden email]>Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.



 








 




By the way, the Tropic of Capricorn is constantly moving.




 




Victor





--
Amos Shapir
 

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Re: Where can the sun cross on only one day a year?

Irv Bromberg
The apparent solar declination can wobble a bit near a solstice, due to the wobbling of Earth's axis.
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Re: Where can the sun cross on only one day a year?

Karl Palmen
In reply to this post by Victor Engel

Dear Victor, Amos,  Moongazer and Calendar People

 

So a clock would be an essential part of the mechanism.

 

Karl

 

16(17(23

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Victor Engel
Sent: 08 January 2018 16:03
To: [hidden email]
Subject: Re: Where can the sun cross on only one day a year?

 

Dear Amos, Moongazer, and Calendar People,

 

Key additional phrase there is "at a specific hour". If the situation is as I speculated, e.g., sunrise, the same location of the rising sun would be at different times except at the intersection of the analemma for non-solstice dates.

 

Victor

 

On Mon, Jan 8, 2018 at 9:57 AM, Amos Shapir <[hidden email]> wrote:

Hi Moongazer and calendar people,

Because of the Sun's analemma, the Sun's position in the sky (azimuth & elevation) at noon -- or at any other specific time of day -- happens at a different place each day of the year, except the longitudinal equinoxes, when the two branches of the figure-8 meet.

Thus it is possible to build a pole or skylight which directs shadow/sunlight to a specific point exactly once a year at a specific hour.

 

On Mon, Jan 8, 2018 at 4:48 PM, Victor Engel <brillig@...> wrote:

 

 

 




 







 







 










--

 

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Re: Where can the sun cross on only one day a year?

Ed Kohout
This may be of help:


Obviously, the sunrise would illuminate this alignment twice a year at sunrise, unless it is the solstice sunrise.

- Ed

********************************************



From: Karl Palmen <[hidden email]>
To: [hidden email]
Sent: Tuesday, January 9, 2018 5:57 AM
Subject: Re: Where can the sun cross on only one day a year?

Dear Victor, Amos,  Moongazer and Calendar People
 
So a clock would be an essential part of the mechanism.
 
Karl
 
16(17(23
 
From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Victor Engel
Sent: 08 January 2018 16:03
To: [hidden email]
Subject: Re: Where can the sun cross on only one day a year?
 
Dear Amos, Moongazer, and Calendar People,
 
Key additional phrase there is "at a specific hour". If the situation is as I speculated, e.g., sunrise, the same location of the rising sun would be at different times except at the intersection of the analemma for non-solstice dates.
 
Victor
 
On Mon, Jan 8, 2018 at 9:57 AM, Amos Shapir <[hidden email]> wrote:
Hi Moongazer and calendar people,
Because of the Sun's analemma, the Sun's position in the sky (azimuth & elevation) at noon -- or at any other specific time of day -- happens at a different place each day of the year, except the longitudinal equinoxes, when the two branches of the figure-8 meet.
Thus it is possible to build a pole or skylight which directs shadow/sunlight to a specific point exactly once a year at a specific hour.


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Re: Where can the sun cross on only one day a year?

Irv Bromberg

Interesting APOD image depicting the position of Sun in Sagittarius at the south solstice.
Read the explanation there.

https://apod.nasa.gov/apod/ap171221.html

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Re: Where can the sun cross on only one day a year?

Jim Riley-4
In reply to this post by Moongazer
There is a similar memorial in Anthem, Arizona. Towards the end of the
video you can see a ledge on the base of the columns (west side)
coming out of shadows.

https://www.youtube.com/watch?v=aQlKR8TbGPY

This demonstrates modeling of the memorial, though the sun's position
is not astronomically modeled.

https://www.youtube.com/watch?v=4G57oE-B9-g

Veteran's Day may be particularly forgiving, since solar noon is not
varying much day to day, so that the sun's azimuth at 11:11 a.m. is
more or less constant.

Optimal months for this phenomena are February, May, July-Early
August, and Late October-Early November.

Using Phoenix (about 30 miles south of Anthem), and the USNO
calculator the altitude and azimuth on November 11 at 11:11 am for
2011 through 2016.

2011 36.8 161.6
2012 37.0 161.6
2013 36.9 161.6
2014 36.9 161.6
2015 36.8 161.6
2016 37.0 161.6

The azimuth angle advances 5.7 degrees between 11:01 and 11:21 so it
is quite reliable as a clock. I found one source that says that the
horizontal alignment over the period from 2011 to 2111 will vary by 24
seconds (from 11:10:58 to 11:11:22). The final alignment is the mean
of that period. Presumably, visitors will be asked to turn off their
smartphones during the solemn occasion, and the military flyover will
be timed to match that year's alignment.

The vertical alignment may be a bit more difficult to get right, since
it varies from year to year, and is quite similar on surrounding
dates.

For November 10, 2016 the sun's altitude at 11:11:11 was 37.1 degrees
and on November 12, 2016 was 36.5 degrees. The difference from
November 11 of 0.3 degrees is less than the apparent diameter of the
solar disk.

If we guesstimate 50 feet from the center of the Great Seal to the
last column, then the aperture in the column needs to be at
50 tan(36.8 degrees) or 37.4 feet.

On November 10, 2016, a sun altitude of 37.0 would project an aperture
49.63 feet, so the sunlight would be slightly off-center of the Great
Seal. On November 12, 2016, a sun altitude of 36.5 would project an
aperture of 50.54 feet, so off center-the other way.

Perhaps the apertures on the five columns are not perfectly in
alignment, making the angle more sensitive while not capturing the
entire solar disk. We're depending on the contrast between the red
bricks in full shadow, with the sunlight reflecting off the white
glass tiles.

While most popular references say that the alignment occurs once per
year, this appears to be conflating the fact that it happens at
11:11:11 (+/- 11 seconds) on November 11 (a specific time on a
specific date of each year, that it only happens that one time per
year). The website for the monument that explains the 22 second
variation in the time, also notes that it happens twice a year, with
the other time in the winter. The other time appears to be 11:40 on
January 30 (at least for Phoenix). Anthem is about 30 miles north of
Phoenix, so the altitude of the sun (near noon) should be about 0.5
degrees lower, but the azimuth pretty much the same. Phoenix (and
Anthem) are about 7 degrees west of the central meridian for the
Mountain Time Zone, the 11:11 and 11:40 are a bit further from mean
solar noon than it might appear.

The altitude varies about 0.3 degrees per day on either side of
November 11. Would it be expected that the altitude would drop and
then elevate to the same level in exactly 80 days between November 11
and January 30? Both are 40 days from December 21, the usual solstice
date. Since the monument is tuned for November 11, it is conceivable
that January 30 is not quite as matched. Or maybe they oscillate. If
the altitude is a bit higher on November 11, indicating that it is
further from the solstice that year, then January 30 would be closer
to the solstice and the altitude lower that year (or annual cycle).

This picture shows the monument at some time other than November 11
(no ceremony), and the sun-light is a bit south of centered on the
Great Seal.

https://twistedsifter.files.wordpress.com/2014/11/anthem-veterans-memorial-arizona-by-renee-palmer-jones-7.jpg?w=640&h=1123

This picture indicates my guess of 50 feet from the last column to
seal was off by a factor of about 2.

https://twistedsifter.files.wordpress.com/2014/11/anthem-veterans-memorial-arizona-by-renee-palmer-jones-4.jpg?w=800&h=557

In the Al Jazeera video the reporter Lucia Newman and Mapuche
historian Hernan Curiñir appear to be based on the shadows in mid-day
sun, which would make their left be towards the south. Notice how he
has Newman come beside him on his left side, so that they are
generally facing west. If it is in the forenoon, they are facing
somewhat north of west. If in the afternoon, they are facing more
southerly. His hand shows a motion from north to south, or maybe west
to east.

This article says that a ceremony took place at sunrise on November
24, 2017. The picture looks photoshopped. The altitude for the sunbeam
is too great for sunrise, even if foreshortened if the camera was
further to the west and shooting up-beam rather than cross-beam. And
if there was a spotlight, it would light a spot and not the whole
ground.

https://www.araucaniacuenta.cl/fue-inaugurado-en-temuco-memorial-por-los-detenidos-desaparecidos-mapuche/

The park shown on the map does exist on the south edge of Temuco,
Chile. Using 38°45' S 72°36' W, sunrise on November 24 is at 6:23 am
(UTC-3) at an azimuth of 117.4 degrees. An ice-filled caldera exists
at Sullipulli about 60 miles at 107 degrees from Temuco. At about 6000
feet higher, its apparent height would be one degree. I suppose there
might be a reflection off the ice field about an hour after sunrise.
This would be sensitive to both altitude and azimuth of the sun, and
only repeated twice a year. The second occurrence on January 17 would
be after the solstice, and perhaps there would be icemelt. But that
would make it hard to repeat from year to year.

Villarica is a more conventional peak, but at about 143 degrees from
Temuco is to far south.

The word that sounds like 'quay' in the interview is 'kuel' in the
article. The only other meanings of 'kuel' I came across were a radio
station in Iowa, and Leet for 'cool'. The use of 'k' in a
Spanish-language article seems odd. Is it used in transliteration of
Mapuche words?

On Mon, 8 Jan 2018 09:51:29 +0100, Moongazer <[hidden email]>
wrote:

>Hi Victor and calendar people,   That Al-Jazeera report is now on YouTube here:  https://www.youtube.com/watch?v=r6rTTTEEBfM  where, if you pause it at 1:05, you can see that the place that the reporter, Lucia Newman, is at is Temuco, an historical stronghold of the Mapuches, where the site of the memorial will be located. Temuco's coordinates are: 38.7359° S, 72.5904° W. So the Sun's crossing "from one side to the other" is not related to its north-south movement at all. So it seems a complete mystery what that crossing is about and why it only occurs on one day in the year.   As for Victor's remarks about Veterans Day, in England and Australia it is called Armistice Day or Remembrance Day, and the Shrine of Remembrance in Melbourne contains a skylight through which the Sun's rays illuminate an inscription at 11:00 on that day each year. (See: https://en.wikipedia.org/wiki/Shrine_of_Remembrance#Architecture_and_features ) It was built before Daylight Saving Time was introduced in
>Victoria and nowadays a mirror adjusts for DST. I guess if the opening is large enough, the effect is the same regardless of calendar jitter, or maybe there are exceptions in some years when it doesn't work.   Moongazer   From: "Victor Engel" <[hidden email]>Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.   https://www.youtube.com/watch?v=DhYO6an0M-I   By the way, the Tropic of Capricorn is constantly moving.   Victor    
--
Jim Riley
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Re: Where can the sun cross on only one day a year?

Karl Palmen
Dear Jim and Calendar People

JIM SAID:
Using Phoenix (about 30 miles south of Anthem), and the USNO
calculator the altitude and azimuth on November 11 at 11:11 am for
2011 through 2016.

2011 36.8 161.6
2012 37.0 161.6
2013 36.9 161.6
2014 36.9 161.6
2015 36.8 161.6
2016 37.0 161.6

KARL ASKS:
What are the results for 1903 (or 2303) and 2096?
Is there a URL for this USNO calculator?

Karl

16(17(24

-----Original Message-----
From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Jim Riley
Sent: 10 January 2018 03:53
To: [hidden email]
Subject: Re: Where can the sun cross on only one day a year?

There is a similar memorial in Anthem, Arizona. Towards the end of the
video you can see a ledge on the base of the columns (west side)
coming out of shadows.

https://www.youtube.com/watch?v=aQlKR8TbGPY

This demonstrates modeling of the memorial, though the sun's position
is not astronomically modeled.

https://www.youtube.com/watch?v=4G57oE-B9-g

Veteran's Day may be particularly forgiving, since solar noon is not
varying much day to day, so that the sun's azimuth at 11:11 a.m. is
more or less constant.

Optimal months for this phenomena are February, May, July-Early
August, and Late October-Early November.

Using Phoenix (about 30 miles south of Anthem), and the USNO
calculator the altitude and azimuth on November 11 at 11:11 am for
2011 through 2016.

2011 36.8 161.6
2012 37.0 161.6
2013 36.9 161.6
2014 36.9 161.6
2015 36.8 161.6
2016 37.0 161.6

The azimuth angle advances 5.7 degrees between 11:01 and 11:21 so it
is quite reliable as a clock. I found one source that says that the
horizontal alignment over the period from 2011 to 2111 will vary by 24
seconds (from 11:10:58 to 11:11:22). The final alignment is the mean
of that period. Presumably, visitors will be asked to turn off their
smartphones during the solemn occasion, and the military flyover will
be timed to match that year's alignment.

The vertical alignment may be a bit more difficult to get right, since
it varies from year to year, and is quite similar on surrounding
dates.

For November 10, 2016 the sun's altitude at 11:11:11 was 37.1 degrees
and on November 12, 2016 was 36.5 degrees. The difference from
November 11 of 0.3 degrees is less than the apparent diameter of the
solar disk.

If we guesstimate 50 feet from the center of the Great Seal to the
last column, then the aperture in the column needs to be at
50 tan(36.8 degrees) or 37.4 feet.

On November 10, 2016, a sun altitude of 37.0 would project an aperture
49.63 feet, so the sunlight would be slightly off-center of the Great
Seal. On November 12, 2016, a sun altitude of 36.5 would project an
aperture of 50.54 feet, so off center-the other way.

Perhaps the apertures on the five columns are not perfectly in
alignment, making the angle more sensitive while not capturing the
entire solar disk. We're depending on the contrast between the red
bricks in full shadow, with the sunlight reflecting off the white
glass tiles.

While most popular references say that the alignment occurs once per
year, this appears to be conflating the fact that it happens at
11:11:11 (+/- 11 seconds) on November 11 (a specific time on a
specific date of each year, that it only happens that one time per
year). The website for the monument that explains the 22 second
variation in the time, also notes that it happens twice a year, with
the other time in the winter. The other time appears to be 11:40 on
January 30 (at least for Phoenix). Anthem is about 30 miles north of
Phoenix, so the altitude of the sun (near noon) should be about 0.5
degrees lower, but the azimuth pretty much the same. Phoenix (and
Anthem) are about 7 degrees west of the central meridian for the
Mountain Time Zone, the 11:11 and 11:40 are a bit further from mean
solar noon than it might appear.

The altitude varies about 0.3 degrees per day on either side of
November 11. Would it be expected that the altitude would drop and
then elevate to the same level in exactly 80 days between November 11
and January 30? Both are 40 days from December 21, the usual solstice
date. Since the monument is tuned for November 11, it is conceivable
that January 30 is not quite as matched. Or maybe they oscillate. If
the altitude is a bit higher on November 11, indicating that it is
further from the solstice that year, then January 30 would be closer
to the solstice and the altitude lower that year (or annual cycle).

This picture shows the monument at some time other than November 11
(no ceremony), and the sun-light is a bit south of centered on the
Great Seal.

https://twistedsifter.files.wordpress.com/2014/11/anthem-veterans-memorial-arizona-by-renee-palmer-jones-7.jpg?w=640&h=1123

This picture indicates my guess of 50 feet from the last column to
seal was off by a factor of about 2.

https://twistedsifter.files.wordpress.com/2014/11/anthem-veterans-memorial-arizona-by-renee-palmer-jones-4.jpg?w=800&h=557

In the Al Jazeera video the reporter Lucia Newman and Mapuche
historian Hernan Curiñir appear to be based on the shadows in mid-day
sun, which would make their left be towards the south. Notice how he
has Newman come beside him on his left side, so that they are
generally facing west. If it is in the forenoon, they are facing
somewhat north of west. If in the afternoon, they are facing more
southerly. His hand shows a motion from north to south, or maybe west
to east.

This article says that a ceremony took place at sunrise on November
24, 2017. The picture looks photoshopped. The altitude for the sunbeam
is too great for sunrise, even if foreshortened if the camera was
further to the west and shooting up-beam rather than cross-beam. And
if there was a spotlight, it would light a spot and not the whole
ground.

https://www.araucaniacuenta.cl/fue-inaugurado-en-temuco-memorial-por-los-detenidos-desaparecidos-mapuche/

The park shown on the map does exist on the south edge of Temuco,
Chile. Using 38°45' S 72°36' W, sunrise on November 24 is at 6:23 am
(UTC-3) at an azimuth of 117.4 degrees. An ice-filled caldera exists
at Sullipulli about 60 miles at 107 degrees from Temuco. At about 6000
feet higher, its apparent height would be one degree. I suppose there
might be a reflection off the ice field about an hour after sunrise.
This would be sensitive to both altitude and azimuth of the sun, and
only repeated twice a year. The second occurrence on January 17 would
be after the solstice, and perhaps there would be icemelt. But that
would make it hard to repeat from year to year.

Villarica is a more conventional peak, but at about 143 degrees from
Temuco is to far south.

The word that sounds like 'quay' in the interview is 'kuel' in the
article. The only other meanings of 'kuel' I came across were a radio
station in Iowa, and Leet for 'cool'. The use of 'k' in a
Spanish-language article seems odd. Is it used in transliteration of
Mapuche words?

On Mon, 8 Jan 2018 09:51:29 +0100, Moongazer <[hidden email]>
wrote:

>Hi Victor and calendar people,   That Al-Jazeera report is now on YouTube here:  https://www.youtube.com/watch?v=r6rTTTEEBfM  where, if you pause it at 1:05, you can see that the place that the reporter, Lucia Newman, is at is Temuco, an historical stronghold of the Mapuches, where the site of the memorial will be located. Temuco's coordinates are: 38.7359° S, 72.5904° W. So the Sun's crossing "from one side to the other" is not related to its north-south movement at all. So it seems a complete mystery what that crossing is about and why it only occurs on one day in the year.   As for Victor's remarks about Veterans Day, in England and Australia it is called Armistice Day or Remembrance Day, and the Shrine of Remembrance in Melbourne contains a skylight through which the Sun's rays illuminate an inscription at 11:00 on that day each year. (See: https://en.wikipedia.org/wiki/Shrine_of_Remembrance#Architecture_and_features ) It was built before Daylight Saving Time was introduced in
>Victoria and nowadays a mirror adjusts for DST. I guess if the opening is large enough, the effect is the same regardless of calendar jitter, or maybe there are exceptions in some years when it doesn't work.   Moongazer   From: "Victor Engel" <[hidden email]>Some time ago, someone posted on facebook an article about a Veteran's Day memorial that lights up a feature only every Veteran's Day at 11:11 o'clock. Of course, those of us who know about calendar jitter know that can't be exactly true.   https://www.youtube.com/watch?v=DhYO6an0M-I   By the way, the Tropic of Capricorn is constantly moving.   Victor    
--
Jim Riley