APOD: Moons at Twilight (2022 Feb 04)

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APOD: Moons at Twilight (2022 Feb 04)

Post by APOD Robot » Fri Feb 04, 2022 5:05 am

Image Moons at Twilight

Explanation: Even though Jupiter was the only planet visible in the evening sky on February 2, it shared the twilight above the western horizon with the Solar System's brightest moons. In a single exposure made just after sunset, the Solar System's ruling gas giant is at the upper right in this telephoto field-of-view from Cancun, Mexico. The snapshot also captures our fair planet's own natural satellite in its young crescent phase. The Moon's disk looms large, its familiar face illuminated mostly by earthshine. But the four points of light lined-up with Jupiter are Jupiter's own large Galilean moons. Top to bottom are Ganymede, [Jupiter], Io, Europa, and Callisto. Ganymede, Io, and Callisto are physically larger than Earth's Moon while water world Europa is only slightly smaller.

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Chris Peterson
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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by Chris Peterson » Fri Feb 04, 2022 5:25 am

APOD Robot wrote: Fri Feb 04, 2022 5:05 am In a single exposure made just after sunset...
While I certainly don't think there's anything dishonest in this image, I'm somewhat skeptical of the claim that it is a single exposure. For the earthshine to be so bright, the crescent should be far more overexposed and appear bloated. Either an awful lot of Photoshop magic was applied to clean it up, or it was some kind of HDR capture (which if it occurred inside the camera, could reasonably be called a "single exposure", even if composited from an internal series).

I'd love to know the imaging and processing details.
Chris

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Bill Y

Re: APOD: Moons at Twilight (2022 Feb 04)

Post by Bill Y » Fri Feb 04, 2022 7:28 am

And since when could you see Jupiter's moons with the naked eye?

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Chris Peterson
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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by Chris Peterson » Fri Feb 04, 2022 7:38 am

Bill Y wrote: Fri Feb 04, 2022 7:28 am And since when could you see Jupiter's moons with the naked eye?
The Galilean moons are bright enough to see with the naked eye. Jupiter's brightness tends to mask them, however. It is possible to block Jupiter with a distant object (power lines work nicely) and then you can readily see the moons if they're aligned with reasonable separation. I've done it a number of times.

(In any case, however, this image is somewhat deeper and has more dynamic range than a naked eye view affords.)
Chris

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Ahmad Jabakenji
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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by Ahmad Jabakenji » Fri Feb 04, 2022 8:51 am

What a brilliant shot. Lovely combination with simplest composition and very impressive quality/details of the pale moon.
Congratulations, sir!.

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Scientific - Technical chief of ASU Lebanon

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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by orin stepanek » Fri Feb 04, 2022 12:27 pm

IMG_1869Fedez.png
Kudos Robert Fedez! A very nice photo!
I do have trouble finding Callisto! OK; I found it! :lol2:
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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by neufer » Fri Feb 04, 2022 5:30 pm

orin stepanek wrote: Fri Feb 04, 2022 12:27 pm
I do have trouble finding Callisto! OK; I found it! :lol2:
[ORANGE] poet malicious delay.
I[O] Eu[R]opa [GAN]ym[E]de Callisto.
Art Neuendorffer

buonafede

Re: APOD: Moons at Twilight (2022 Feb 04)

Post by buonafede » Fri Feb 04, 2022 8:24 pm

What I don't understand is how the Moon can appear so large - Isn't this the so called "moon illusion " at work?

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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by johnnydeep » Fri Feb 04, 2022 9:15 pm

neufer wrote: Fri Feb 04, 2022 5:30 pm
orin stepanek wrote: Fri Feb 04, 2022 12:27 pm
I do have trouble finding Callisto! OK; I found it! :lol2:
[ORANGE] poet malicious delay.
I[O] Eu[R]opa [GAN]ym[E]de Callisto.
Nice. There are at least 100 thousand more - https://new.wordsmith.org/anagram/anagr ... source=adv

Such as:

Paramedical Oenology Suite
Academia Liege Lousy Proton
etc.
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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by Chris Peterson » Fri Feb 04, 2022 9:22 pm

buonafede wrote: Fri Feb 04, 2022 8:24 pm What I don't understand is how the Moon can appear so large - Isn't this the so called "moon illusion " at work?
No. The Moon illusion only works visually. In an image you can make the Moon look as big or small as you want, simply by choosing the right lens or the right cropping. The angular size of the Moon in this image is consistent with all the other features we see.
Chris

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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by johnnydeep » Fri Feb 04, 2022 10:08 pm

Chris Peterson wrote: Fri Feb 04, 2022 9:22 pm
buonafede wrote: Fri Feb 04, 2022 8:24 pm What I don't understand is how the Moon can appear so large - Isn't this the so called "moon illusion " at work?
No. The Moon illusion only works visually. In an image you can make the Moon look as big or small as you want, simply by choosing the right lens or the right cropping. The angular size of the Moon in this image is consistent with all the other features we see.
And specifically, the Moon and Jupiter look to be about 3.5 degrees apart here (given that the moon is .5 degrees wide).
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by neufer » Sat Feb 05, 2022 3:33 am

https://en.wikipedia.org/wiki/Moonfall_(film) wrote:
<<Moonfall is a 2022 science fiction disaster film co-written, directed, and co-produced by Roland Emmerich. The film was shot in Montreal on a $146 million production budget, making it one of the most expensive independently produced films of all-time. Moonfall was released in the United States on February 4, 2022.

Astronaut Brian Harper is working on a satellite on a 2011 Space Shuttle mission, when a mysterious black swarm attacks the mission and kills a crewmate. Back on Earth, nobody believes his explanation, human error is blamed, and Harper is fired. Ten years later, conspiracy theorist K.C. Houseman, who believes the Moon is an artificial megastructure, steals time on a telescope and discovers that the Moon's orbit is getting closer to Earth. He attempts to share his findings with Harper, who dismisses him, leading K.C. to go public on social media. As the Moon falls closer to earth, cataclysmic disasters mount: tsunamis, gravity abnormalities, and atmospheric dissipation. It is revealed within NASA that Apollo 11 discovered the abnormalities in the Moon, and the two minute blackout was to block out inexplicable data, in which the Moon supposedly resonated strongly from the impact of Apollo 11's jettisoned fuel tank. A program called ZX7 created an EMP to attempt to kill the swarm, which is brought out of storage. A Space Shuttle is brought out of a museum and prepared for launch. KC, Harper, and deputy director Jocinda "Jo" Fowler launch with the EMP, narrowly escaping a tsunami.

As they enter the Moon, they discover that the swarm is siphoning off energy generated by a white dwarf at the center of the Moon, causing the artificial megastructure's orbit to destabilize, due to its power source being compromised. The megastructure was constructed by ancestors of humanity, billions of years in the past, as an ark while fleeing artificial intelligence that grew too strong and attacked. The swarm is one of those AIs that found the Moon, which was the last ark. The President gave the Chairman of the Joint Chiefs of Staff, General Jenkins order to launch a Nuclear Strike towards the Moon. However the Air Force Chief of Staff, General Doug Davidson refused to carry out the Nuclear Strike order, so that he can save the lives of his former wife, Fowler, and both Harper and Houseman.

K.C. sacrifices himself to lure the swarm to the EMP, and detonates it. With power restored, the Moon returns to its regular orbit. The operating system of the Moon reveals that it has stored K.C.'s consciousness, appearing to him as his mother, and states that they need to get to work.>>
Art Neuendorffer

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Re: APOD: Moons at Twilight (2022 Feb 04)

Post by orin stepanek » Sat Feb 05, 2022 2:01 pm

Orin

Smile today; tomorrow's another day!