APOD: Saturn at Night (2021 Sep 11)

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APOD: Saturn at Night (2021 Sep 11)

Post by APOD Robot » Sat Sep 11, 2021 4:05 am

Image Saturn at Night

Explanation: Still bright in planet Earth's night skies, good telescopic views of Saturn and its beautiful rings often make it a star at star parties. But this stunning view of Saturn's rings and night side just isn't possible from telescopes closer to the Sun than the outer planet. They can only bring Saturn's day into view. In fact, this image of Saturn's slender sunlit crescent with night's shadow cast across its broad and complex ring system was captured by the Cassini spacecraft. A robot spacecraft from planet Earth, Cassini called Saturn orbit home for 13 years before it was directed to dive into the atmosphere of the gas giant on September 15, 2017. This magnificent mosaic is composed of frames recorded by Cassini's wide-angle camera only two days before its grand final plunge. Saturn's night will not be seen again until another spaceship from Earth calls.

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Re: APOD: Saturn at Night (2021 Sep 11)

Post by orin stepanek » Sat Sep 11, 2021 1:15 pm

LastRingPortrait_Cassini_1080.jpg
all the difference between night and day! :mrgreen:
heic1917a.jpg
Nice photos of Saturn! 8-)
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smaismrmilmepoetaleumibunenugttauiras

Post by neufer » Sat Sep 11, 2021 3:11 pm

https://en.wikipedia.org/wiki/Rings_of_Saturn wrote:
<<Galileo Galilei was the first to observe the rings of Saturn in 1610 using his telescope, but was unable to identify them as such. He wrote to the Duke of Tuscany that "The planet Saturn is not alone, but is composed of three, which almost touch one another and never move nor change with respect to one another. They are arranged in a line parallel to the zodiac, and the middle one (Saturn itself) is about three times the size of the lateral ones." He also described the rings as Saturn's "ears". In 1612 the Earth passed through the plane of the rings and they became invisible. Mystified, Galileo remarked "I do not know what to say in a case so surprising, so unlooked for and so novel." He mused, "Has Saturn swallowed his children?" — referring to the myth of the Titan Saturn devouring his offspring to forestall the prophecy of them overthrowing him. He was further confused when the rings again became visible in 1613.

Early astronomers used anagrams as a form of commitment scheme to lay claim to new discoveries before their results were ready for publication. Galileo used smaismrmilmepoetaleumibunenugttauiras for Altissimum planetam tergeminum observavi ("I have observed the most distant planet to have a triple form") for discovering the rings of Saturn.

In 1657 Christopher Wren became Professor of Astronomy at Gresham College, London. He had been making observations of the planet Saturn from around 1652 with the aim of explaining its appearance. His hypothesis was written up in De corpore saturni, in which he came close to suggesting the planet had a ring. However, Wren was unsure whether the ring was independent of the planet, or physically attached to it. Before Wren's theory was published Christiaan Huygens presented his theory of the rings of Saturn. Immediately Wren recognised this as a better hypothesis than his own and De corpore saturni was never published. Robert Hooke was another early observer of the rings of Saturn, and noted the casting of shadows on the rings.>>
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Re: smaismrmilmepoetaleumibunenugttauiras

Post by johnnydeep » Sat Sep 11, 2021 9:09 pm

neufer wrote:
Sat Sep 11, 2021 3:11 pm
https://en.wikipedia.org/wiki/Rings_of_Saturn wrote: ...
<<Early astronomers used anagrams as a form of commitment scheme to lay claim to new discoveries before their results were ready for publication. Galileo used smaismrmilmepoetaleumibunenugttauiras for Altissimum planetam tergeminum observavi ("I have observed the most distant planet to have a triple form") for discovering the rings of Saturn.>>
That's kinda cool. I guess that provides a simple way to publish your result in an "encrypted" form, which you can prove to be the authentic author of later by revealing the anagram? But it will only work as long as no one else is smart enough to figure out the anagram!
Last edited by johnnydeep on Sat Sep 11, 2021 10:46 pm, edited 1 time in total.
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Re: smaismrmilmepoetaleumibunenugttauiras

Post by neufer » Sat Sep 11, 2021 10:23 pm

Click to play embedded YouTube video.
johnnydeep wrote:
Sat Sep 11, 2021 9:09 pm


That's kinda cool. I guess that provides a simple way to publish your result in an "encrypted" form, which you can prove to be the authentic author of later by revealing the anagram?

But it will only work as long as no one else is smart enough to figure out the anagram!
We are currently plowing through every possible 37 letter combination of the anagram.

But since there are 13,763,753,091,226,345,046,315,979,581,580,902,400 million permutations it's going to take us about two and a half days to analyze them all.
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Re: smaismrmilmepoetaleumibunenugttauiras

Post by neufer » Sat Sep 11, 2021 10:47 pm

https://en.wikipedia.org/wiki/Honorificabilitudinitatibus#Use_in_Baconianism wrote:
<<Honorificabilitudinitatibus is the dative and ablative plural of the medieval Latin word honōrificābilitūdinitās, which can be translated as "the state of being able to achieve honours." At 27 letters, it is the second-longest word in the English language featuring only alternating consonants and vowels.

The word is spoken by the country bumpkin Costard in Act V, Scene 1 of the play Love's Labour's Lost after an absurdly pretentious dialogue between the pedantic schoolmaster Holofernes and his friend Sir Nathaniel. The two pedants converse in a mixture of Latin and florid English. When Moth, a witty young servant, enters, Costard says of the pedants: O, they have lived long on the alms-basket of words, I marvel thy master hath not eaten thee for a word; for thou art not so long by the head as honorificabilitudinitatibus: thou art easier swallowed than a flap-dragon.

The word has been used by adherents of the Baconian theory who believe Shakespeare's plays were written in steganographic cypher by Francis Bacon. In 1905 Isaac Hull Platt argued that it was an anagram for hi ludi, F. Baconis nati, tuiti orbi, Latin for "these plays, F. Bacon's offspring, are preserved for the world". His argument was given wide circulation by Edwin Durning-Lawrence in 1910, complete with a cryptonumerical attempt to prove it justified. The anagram assumes that Bacon would have Latinized his name as "Baco" or "Bacon" (the genitive case of which is "Baconis") rather than "Baconus", with genitive "Baconi".

It is far from the only possible anagram. In 1898, Paget Toynbee noted that the word contains a glorification of Dante by himself as its letters could be rearranged to form the phrase Ubi Italicus ibi Danti honor fit (Where there is an Italian, there honour is paid to Dante). In the 1970s, John Sladek noted that the word could also be anagrammatized as I, B. Ionsonii, uurit [writ] a lift'd batch, thus "proving" that Shakespeare's works were written by Ben Jonson. In 2012, in a column for the Calcutta Telegraph, Stephen Hugh-Jones mocked it with the deliberately anachronistic "If I built it in, is author ID Bacon?", attributing this to a derisive William Shakespeare; and counter-"proved" that Shakespeare wrote Bacon by converting the latter's famous opening phrase "What is truth, said jesting Pilate..." into "Truth? A lasting jape. Hide it. WS".>>
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Re: smaismrmilmepoetaleumibunenugttauiras

Post by johnnydeep » Sat Sep 11, 2021 10:51 pm

neufer wrote:
Sat Sep 11, 2021 10:23 pm
Click to play embedded YouTube video.
johnnydeep wrote:
Sat Sep 11, 2021 9:09 pm


That's kinda cool. I guess that provides a simple way to publish your result in an "encrypted" form, which you can prove to be the authentic author of later by revealing the anagram?

But it will only work as long as no one else is smart enough to figure out the anagram!
We are currently plowing through every possible 37 letter combination of the anagram.

But since there are 13,763,753,091,226,345,046,315,979,581,580,902,400 million permutations it's going to take us about two and a half days to analyze them all.
Well, sure, a pure brute force technique won’t work well, but knowing that all the original letters are there, and that they presumably make up actual words, cuts down the search space significantly. Plus, some people are REALLY good at anagrams! But I think even a simple Caesar substitution cipher applied before or after (either gives the same result!) would make it much harder.
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Vorteks

Re: APOD: Saturn at Night (2021 Sep 11)

Post by Vorteks » Sun Sep 12, 2021 9:09 pm

The sun-ward half of the rings appear to be slightly more dimly lit than the illuminated parts of the half of the rings nearer the camera in the picture.
I would have expected the sun-ward side to be brighter, if anything, due to reflected light from Saturn.
Is that difference real or a photographic artifact?

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Re: APOD: Saturn at Night (2021 Sep 11)

Post by johnnydeep » Sun Sep 12, 2021 10:50 pm

Vorteks wrote:
Sun Sep 12, 2021 9:09 pm
The sun-ward half of the rings appear to be slightly more dimly lit than the illuminated parts of the half of the rings nearer the camera in the picture.
I would have expected the sun-ward side to be brighter, if anything, due to reflected light from Saturn.
Is that difference real or a photographic artifact?
Good observation. I see what you mean. Not sure what’s causing that, but there is a fairly sharp dividing line between the two brightness levels. Hopefully someone else will weigh in with a better answer for you.
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Re: APOD: Saturn at Night (2021 Sep 11)

Post by neufer » Mon Sep 13, 2021 1:36 am

johnnydeep wrote:
Sun Sep 12, 2021 10:50 pm
Vorteks wrote:
Sun Sep 12, 2021 9:09 pm

The sun-ward half of the rings appear to be slightly more dimly lit than the illuminated parts of the half of the rings nearer the camera in the picture. I would have expected the sun-ward side to be brighter, if anything, due to reflected light from Saturn.

Is that difference real or a photographic artifact?
Good observation. I see what you mean. Not sure what’s causing that, but there is a fairly sharp dividing line between the two brightness levels. Hopefully someone else will weigh in with a better answer for you.
This mosaic of 42 Cassini wide-angle shots appears to be reprocessed to make use of the full dynamic range of each wide-angle shot. This artificially brights almost all of the dim rings except for those rings in wide-angle shots that include the bright Saturn crescent.
https://photojournal.jpl.nasa.gov/catalog/PIA17218 wrote: <<After more than 13 years at Saturn, and with its fate sealed, NASA's Cassini spacecraft bid farewell to the Saturnian system by firing the shutters of its wide-angle camera and capturing this last, full mosaic of Saturn and its rings two days before the spacecraft's dramatic plunge into the planet's atmosphere.

During the observation, a total of 80 wide-angle images were acquired in just over two hours. This view is constructed from 42 of those wide-angle shots, taken using the red, green and blue spectral filters, combined and mosaicked together to create a natural-color view.>>
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Re: APOD: Saturn at Night (2021 Sep 11)

Post by johnnydeep » Mon Sep 13, 2021 12:09 pm

neufer wrote:
Mon Sep 13, 2021 1:36 am
johnnydeep wrote:
Sun Sep 12, 2021 10:50 pm
Vorteks wrote:
Sun Sep 12, 2021 9:09 pm

The sun-ward half of the rings appear to be slightly more dimly lit than the illuminated parts of the half of the rings nearer the camera in the picture. I would have expected the sun-ward side to be brighter, if anything, due to reflected light from Saturn.

Is that difference real or a photographic artifact?
Good observation. I see what you mean. Not sure what’s causing that, but there is a fairly sharp dividing line between the two brightness levels. Hopefully someone else will weigh in with a better answer for you.
This mosaic of 42 Cassini wide-angle shots appears to be reprocessed to make use of the full dynamic range of each wide-angle shot. This artificially brights almost all of the dim rings except for those rings in wide-angle shots that include the bright Saturn crescent.
https://photojournal.jpl.nasa.gov/catalog/PIA17218 wrote: <<After more than 13 years at Saturn, and with its fate sealed, NASA's Cassini spacecraft bid farewell to the Saturnian system by firing the shutters of its wide-angle camera and capturing this last, full mosaic of Saturn and its rings two days before the spacecraft's dramatic plunge into the planet's atmosphere.

During the observation, a total of 80 wide-angle images were acquired in just over two hours. This view is constructed from 42 of those wide-angle shots, taken using the red, green and blue spectral filters, combined and mosaicked together to create a natural-color view.>>
Thanks. That makes sense. So, essentially, because the upper half includes the bright crescent, the ring halves on that side will look dimmer due to the way the image processing was done.
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Re: APOD: Saturn at Night (2021 Sep 11)

Post by Chris Peterson » Mon Sep 13, 2021 12:56 pm

johnnydeep wrote:
Mon Sep 13, 2021 12:09 pm
Thanks. That makes sense. So, essentially, because the upper half includes the bright crescent, the ring halves on that side will look dimmer due to the way the image processing was done.
That's certainly possible, although if so, it represents a processing failure.
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Re: APOD: Saturn at Night (2021 Sep 11)

Post by neufer » Mon Sep 13, 2021 3:34 pm

ae22b4085120a91dc725f8641e6e5b2a--mad-magazine-magazine-covers.jpg
Chris Peterson wrote:
Mon Sep 13, 2021 12:56 pm
johnnydeep wrote:
Mon Sep 13, 2021 12:09 pm

That makes sense. So, essentially, because the upper half includes the bright crescent, the ring halves on that side will look dimmer due to the way the image processing was done.
That's certainly possible, although if so, it represents a processing failure.
  • I kinda like it, myself.
I don't want the shiny crescent to dominate the picture.

(Note: Saturn's rings from the back are quite dark in comparison because every ring snowball ls a tiny and unresolved crescent.)
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Re: APOD: Saturn at Night (2021 Sep 11)

Post by Chris Peterson » Mon Sep 13, 2021 3:39 pm

neufer wrote:
Mon Sep 13, 2021 3:34 pm
ae22b4085120a91dc725f8641e6e5b2a--mad-magazine-magazine-covers.jpg
Chris Peterson wrote:
Mon Sep 13, 2021 12:56 pm
johnnydeep wrote:
Mon Sep 13, 2021 12:09 pm

That makes sense. So, essentially, because the upper half includes the bright crescent, the ring halves on that side will look dimmer due to the way the image processing was done.
That's certainly possible, although if so, it represents a processing failure.
  • I kinda like it, myself.
I don't want the shiny crescent to dominate the picture.

(Note: Saturn's rings from the back are quite dark in comparison because every ring snowball ls a tiny and unresolved crescent.)
There's no reason for the crescent to dominate with good processing. The failure isn't in mapping the dynamic range as broadly as possible, it's doing it separately for each frame (assuming that's what was done). The failure results in a loss of relative brightness. No matter how the source intensities are mapped to the output intensities, we should never have a situation where two pixels shift their relative intensities with respect to each other. That is, where one is darker in the source, it should be darker in the final version. That's a basic rule of astronomical imaging processing.
Chris

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