APOD: Blue Danube Analemma (2016 Jul 29)

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Expand view Topic review: APOD: Blue Danube Analemma (2016 Jul 29)

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by neufer » Sat Jul 30, 2016 1:27 am

Chris Peterson wrote:
MarkBour wrote:
I was wondering why the Danube looked so beautifully blue.
I've been many times on or along the Danube, and I'm sorry to report that it is generally the same muddy green color that virtually all European rivers are once they're out of the mountains.
http://www.ssqq.com/travel//danube2016bluedanube.htm wrote:

<<In 1866, following Vienna's horrible defeat at the hands of the Prussians and the Italians, Johann Herbeck, master of the Vienna Men’s Choral Society, commissioned Johann Strauss to write a Waltz to lift the spirits of the people. Strauss had just read a poem by Karl Beck. Each stanza ended with the line: ‘By the Danube, the beautiful blue Danube’. Now Strauss had both the inspiration and the title he needed for his new work. Only one problem... oddly enough, at the moment the beautiful blue Danube could hardly be described as blue. It seems that ever since the recent flood, the muddy Danube had been closer to red-brown in color. Nor did anyone in Vienna even like the Danube River. All the Danube ever did was cause problems. Not only was an entire season of crops ruined by the flood, no one dared live anywhere near it. Due to flooding concerns, Viennese engineers avoided going anywhere close to this dangerous river. Consequently, unlike Budapest, Vienna's downstream neighbor, Vienna didn't want anything to do with the massive river. Therefore at the time Strauss wrote his waltz, the river didn’t even flow through Vienna. It wasn’t until 1970 that technology made it safe to finally allow Vienna to expand to the banks of the Danube.

But Strauss didn’t let small details like these deter him. He took to to writing his uplifting song with great passion. In 1867, Johann Strauss composed a Waltz titled An der schönen, blauen Donau. The song got off to a very slow start. It didn't help that Josef Weyl ruined the song. Weyl was an Austrian humorist affiliated with the Choral Society. Weyl decided to add humorous lyrics to the song: “Wiener seid’s froh! Oho! Wieso?” (“Viennese be happy! Oho! But why?”). Weyl's satirical lyrics ridiculed the lost war, the bankrupt city and its politicians.

Strauss believed in his Waltz, but agreed the lyrics were pure sabotage. So he debuted an orchestral version of his song in Paris later in the year at the 1867 World Exhibition. Without the lyrics, the song was greatly improved. The Parisians and the visitors to the World Exhibition absolutely loved the song. Once the Parisians made such a fuss, now the Austrians began to pay better attention. With the lyrics removed, they too embraced the song.>>

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Chris Peterson » Sat Jul 30, 2016 12:30 am

MarkBour wrote:I was wondering why the Danube looked so beautifully blue.
I've been many times on or along the Danube, and I'm sorry to report that it is generally the same muddy green color that virtually all European rivers are once they're out of the mountains.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by alter-ego » Sat Jul 30, 2016 12:28 am

Chris Peterson wrote:
Fred the Cat wrote:What would life be like in a world without analemma's?
Not much different. That would just required a highly circular orbit, and we'd lose the east/west component. A little more extreme would be to have no axial tilt, eliminating the north/south component. That would eliminate seasons, but I don't think that would change the nature of life much.
That's not quite right. A circular orbit does not eliminate east-west motion.
Orbital ellipticity is solely responsible for the asymmetry of the analemma's figure-8 shape, and it affects the magnitude of east-west motion by only ~1/3. For a perfectly circular orbit, the figure-8 is symmetric east-west and north-south. The range of solar declination remains the same, and there's only ~33% reduction in east-west motion. For a circular orbit, the equinoxes occur the intersection point, i.e. the sun is neither slow nor fast at both equinoxes. Now If only the obliquity is reduced to 0°, solar declination remains constant but the east-west motion is about 1/2 the normal range.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by geckzilla » Sat Jul 30, 2016 12:10 am

heehaw: please note the small edit to your post.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by heehaw » Fri Jul 29, 2016 11:23 pm

Second try at that link (the story is really worth reading!)
https://en.wikipedia.org/wiki/The_Martians_(scientists) <--- if it doesn't work, it is failure of the final ) to be included. Put it in by hand!

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by heehaw » Fri Jul 29, 2016 11:20 pm

MarkBour wrote:
neufer wrote: A lot of Budapest born & educated physicists who escaped demagogues to become Americans ...
Thanks for that interesting list, Art. I was wondering why the Danube looked so beautifully blue. Wouldn't that mean it was star-bursting? :D But you've answered that ... we have indeed had quite a burst of physics and math stars coming from there. I did not realize that Von Neumann, one of my favorites, was born in Budapest.
Von Neumann was one of a team: https://en.wikipedia.org/wiki/The_Martians_(scientists)

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by MarkBour » Fri Jul 29, 2016 8:37 pm

neufer wrote: A lot of Budapest born & educated physicists who escaped demagogues to become Americans ...
Thanks for that interesting list, Art. I was wondering why the Danube looked so beautifully blue. Wouldn't that mean it was star-bursting? :D But you've answered that ... we have indeed had quite a burst of physics and math stars coming from there. I did not realize that Von Neumann, one of my favorites, was born in Budapest.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Fred the Cat » Fri Jul 29, 2016 7:55 pm

neufer wrote: A lot of Budapest born & educated physicists who escaped demagogues to become Americans:
I had to look up that word. Demagogue. It may soon be time to visit Hungary for a while. :roll:

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by neufer » Fri Jul 29, 2016 7:25 pm

Fred the Cat wrote:
neufer wrote:
That is something Art. After the Hillarious speech last night you'd think the US is the center of the universe. Our country is worthy of pride but the world makes science tick.
A lot of Budapest born & educated physicists who escaped demagogues to become Americans:
https://en.wikipedia.org/wiki/Theodore_von_K%C3%A1rm%C3%A1n wrote:
<<Theodore von Kármán (May 11, 1881 Budapest - May 6, 1963 Aachen, West Germany) was a Hungarian-American mathematician, aerospace engineer and physicist who was active primarily in the fields of aeronautics and astronautics. He is responsible for many key advances in aerodynamics, notably his work on supersonic and hypersonic airflow characterization. He is regarded as the outstanding aerodynamic theoretician of the twentieth century.>>
https://en.wikipedia.org/wiki/Leo_Szilard wrote:
<<Leo Szilard (February 11, 1898, Budapest – May 30, 1964, La Jolla, California) was a Jewish Hungarian-born physicist and inventor. He conceived the nuclear chain reaction in 1933, patented the idea of a nuclear reactor with Enrico Fermi, and in late 1939 wrote the letter for Albert Einstein's signature that resulted in the Manhattan Project that built the atomic bomb.
https://en.wikipedia.org/wiki/Eugene_Wigner wrote:
<<Eugene Paul "E. P." Wigner (November 17, 1902, Budapest - January 1, 1995 Princeton, New Jersey) was a Hungarian-American theoretical physicist and mathematician. He received half of the Nobel Prize in Physics in 1963 "for his contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles".>>
https://en.wikipedia.org/wiki/John_von_Neumann wrote:
<<John von Neumann (December 28, 1903, Budapest - February 8, 1957, Washington, D.C.) was a Hungarian-American pure and applied mathematician, physicist, inventor, computer scientist, and polymath. He made major contributions to a number of fields, including mathematics (foundations of mathematics, functional analysis, ergodic theory, geometry, topology, and numerical analysis), physics (quantum mechanics, hydrodynamics and quantum statistical mechanics), economics (game theory), computing (Von Neumann architecture, linear programming, self-replicating machines, stochastic computing), and statistics.>>

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Fred the Cat » Fri Jul 29, 2016 6:01 pm

neufer wrote:
https://en.wikipedia.org/wiki/Budapest#Etymology wrote:
<<"Budapest" is the combination of the city names Buda and Pest, which were united into a single city in 1873. The origins of the names Buda and Pest are obscure. Buda [may derive] from the Slavic word вода, voda ("water"), a translation of the Latin name Aquincum, which was the main Roman settlement in the region. Pest [may originate] from the Slavic word for cave (most closely related to Bulgarian and Macedonian: пещера, peștera), or oven (Bulgarian: пещ, peșt), in reference either to a cave where fires burned or to a local limekiln.>>
https://www.google.com/#q=hungarian+physicists
http://www.scientificamerican.com/artic ... of-nature/
That is something Art. After the Hillarious speech last night you'd think the US is the center of the universe. Our country is worthy of pride but the world makes science tick. And some people think science is square? Who knows – in some way they may be right. :wink:

Somethings are still amiss in physics. :?:

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by SciFan1250 » Fri Jul 29, 2016 5:40 pm

Thank you, Chris L Peterson. Now I understand what I was seeing.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Chris Peterson » Fri Jul 29, 2016 5:11 pm

SciFan1250 wrote:My question is how can the sun, positioned towards the front of the camera cast a shadow that also falls toward the front of the camera? This defies the physics of light, does it not?
The laws of physics are doing just fine.

The apparent angle of shadows can be very confusing to interpret in wide angle images. What exactly is "in front" of the camera? Consider the brick road in the foreground. It is completely straight, running north-south (north on the left, south on the right). That's consistent with the images being made near local noon- the Sun is to the south, so we see it over the southern end of the road. Note the photographer's shadow. It is pointing north, and on his north, just as we'd expect. All the shadows are pointing north. This is particularly easy to see with the guard rail posts. Their shadows point north, but in this wide angle image they also appear to point in many different directions. But that's just a projection artifact.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by SciFan1250 » Fri Jul 29, 2016 4:57 pm

My question is how can the sun, positioned towards the front of the camera cast a shadow that also falls toward the front of the camera? This defies the physics of light, does it not?

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Fred the Cat » Fri Jul 29, 2016 4:53 pm

Is "analemma" a made up word for when an astrophotographer is "anal" but has a "dilemma" on what to do?

Just kidding. I do admire their fortitude and applaud the patience they all must exhibit to give us great images. :clap:

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Whiskybreath » Fri Jul 29, 2016 4:36 pm

Case wrote:... The photographer seems to be located at (47.471653,19.064346)....
So nice that a tour bus has parked on that spot. Your photography must have a lot of fans!

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Chris Peterson » Fri Jul 29, 2016 3:38 pm

dkp wrote:Is this a fake? Only the last image of the sun shows lens flaring. They all should.
No, because all the images were exposed so the Sun would be a disk, not overexposed. But one image was exposed for the daylit scene, and for that the Sun was necessarily overexposed.

Some analemma images prevent that by shooting their foreground image at a different time of day, when the Sun is out of the field. But that produces unexpected shadows.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by neufer » Fri Jul 29, 2016 3:37 pm

https://en.wikipedia.org/wiki/Budapest#Etymology wrote:
<<"Budapest" is the combination of the city names Buda and Pest, which were united into a single city in 1873. The origins of the names Buda and Pest are obscure. Buda [may derive] from the Slavic word вода, voda ("water"), a translation of the Latin name Aquincum, which was the main Roman settlement in the region. Pest [may originate] from the Slavic word for cave (most closely related to Bulgarian and Macedonian: пещера, peștera), or oven (Bulgarian: пещ, peșt), in reference either to a cave where fires burned or to a local limekiln.>>
https://www.google.com/#q=hungarian+physicists
http://www.scientificamerican.com/artic ... of-nature/

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by PJ Veber » Fri Jul 29, 2016 3:25 pm

I think someone should pen a tune called *The Blue Danube Analemma*...

Such a great image, I had to call my hubby at work to make sure he saw it. !:]

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by dkp » Fri Jul 29, 2016 3:16 pm

Is this a fake? Only the last image of the sun shows lens flaring. They all should.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Chris Peterson » Fri Jul 29, 2016 3:15 pm

Fred the Cat wrote:What would life be like in a world without analemma's?
Not much different. That would just required a highly circular orbit, and we'd lose the east/west component. A little more extreme would be to have no axial tilt, eliminating the north/south component. That would eliminate seasons, but I don't think that would change the nature of life much.
Or when the Earth becomes tidally locked to the Moon?
Now we're talking about a planet with radically different conditions. Probably with an extreme climate system. Life evolving in such a place might be quite different. Probably not the sort of place we'd expect complex lifeforms.

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Fred the Cat » Fri Jul 29, 2016 2:42 pm

What would life be like in a world without analemma's? Or when the Earth becomes tidally locked to the Moon?

Very boring but if the Sun, Earth and Moon were tidally locked? At least half the Earth might get to see an eclipsed moon every night. :?: And light pollution? :idea: Guess it depends on the side. 8-)

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by mjsakers » Fri Jul 29, 2016 1:13 pm

@Cousin Ricky - Yes! This is one of my favorite things to do! Sometimes very challenging when the clues are scarce. Found this one!

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by vanamonde81 » Fri Jul 29, 2016 12:50 pm

Hi Case,

You are right, I was standing exactly at the position you linked. I am working in the office building visible at the right edge of the photo.

Budapest is a beautiful city indeed. If you have a free week don't hesitate to visit here, you won't regret! ;-)

György

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Case » Fri Jul 29, 2016 11:54 am

Haha, I tried looking it up too. The panorama covers nearly full circle, about 340°I would guess. The nearby bridge with the distinct street light poles (?) to the south seems to be the Rákóczi Bridge. The photographer seems to be located at (47.471653,19.064346). The road between him and the river is at a lower level, according to StreetView, which is more obvious from another perspective. Looks like an interesting city to visit. :ssmile:

Re: APOD: Blue Danube Analemma (2016 Jul 29)

by Cousin Ricky » Fri Jul 29, 2016 11:52 am

Have you ever gone to Google Maps to find a street view of these locations? This one was easy to find.

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