APOD: Rio Morning Moonset (2011 Apr 20)

[APOD Robot]

Rio Morning Moonset

Explanation: As the Sun rose, a nearly full Moon set in this serene seaside vista captured last Monday from Rio de Janeiro, Brazil. In the foreground, the reddened early morning sunlight illuminates a stretch of South Atlantic coastline. Looking toward the west, in a scene that is a familiar one to Rio's Ipanema beach goers, the favela Vidigal is nestled below the twin peaks of Morro Dois Irmãos (Two Brothers Hill). This well-composed multiple-exposure image recorded the steady progress of the dramatic moonset with a 6.5 minute gap between each frame. Flying from their nests at the break of dawn, all the ocean birds appear only in the last single frame.

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[owlice]

Wow; that's lovely.

[Beyond]

Shades of Alfred Hitchcock!

[BMAONE23]

Many moons ago our grandfathers first stepped foot in this beautiful country........and today, that same moon still sets there

[agulesin]

"Moonset?" my first words on seeing today's APOD: "There's something wrong with that..."

of course we're used to seeing it set in the northern hemisphere, never seen it set anywhere else before! How narrow-minded people can be!

Many thanks to Babek for sharing this wonderful photo...

[alphachapmtl]

After the next landslide, they will say "Who knew this could happen".
I knew.

[alphachapmtl]

"Moonset?" my first words on seeing today's APOD: "There's something wrong with that..."

What do you mean?

[orin stepanek]

I liked today's APOD! I'm glad our planet has a moon.

[timbelina]

Hey all!

First up, great image! Thanks.

Second up, I'm confused... I understand (more or less the general idea of how the photos are superimposed, but at first glance, the resulting image looks odd to me because when the moon is higher (further from dawn) it looks brighter, but when it is lower (near dawn) it looks darker. Now, I think it get it: I guess its because while the sky is still dark before dawn, the moon appears brighter, and that's how it looks in the image. But why is it that near dawn, not only does the moon appear less distinct, the clouds around the horizon also appear dark. i.e. There seems to be a conflict: When the moon is up high it should seem bright (and it does) but the sky should be dark (its not). By contrast, at dawn, the moon should be less distinct (it is) but only because its being viewed against a brighter sky (but in the image the horizon is dark).

Ok, that's a long way of saying I'm confused

All explanations most welcome!

Thanks,
Tim.

[owlice]

when the moon is higher (further from dawn)

The moon is setting, not rising.

[timbelina]

Heya!

> The moon is setting, not rising.

Yep. I get that... I think... except that the moon set at dawn doesn't it? And at dawn the sky is getting brighter. So, when the moon is low, its nearly set, and its nearly dawn, so the sky should be bright. But in the image, the sky is dark when the moon sets (low) and light when the moon is high.

I'm sure I'm confused... just so confused that I don't even understand my confusion

CU,
Tim.

[bystander]

The lighting would be a composite of all the frames with most of the light in the image (the sky and landscape) would come from the image with the brightest sky (the last single frame). Each of the moon images appear only in one frame.

[moonstruck]

That is just soo neat.

[neufer]

Click to play embedded YouTube video.

<<The word "Ipanema" comes from the old Tupi language, meaning "bad water." In this case, it means bad for fishing, since the waves die too close to the sand, pushing fish away. Two mountains called the "Dois Irmãos" (Two Brothers) rise at the western end of the beach. The beach is divided into segments by marks known as "postos" (lifeguard towers). Beer is sold everywhere on the beach along with the traditional cachaça. There are always circles of people playing football, volleyball, and footvolley, a combination sport of volleyball and football originated in Brazil.>>

[drintoul]

Nice image! BTW, the "ocean birds" are Magnificent Frigatebirds (Fregata magnificens).

[Chris Peterson]

Second up, I'm confused... I understand (more or less :-) the general idea of how the photos are superimposed, but at first glance, the resulting image looks odd to me because when the moon is higher (further from dawn) it looks brighter, but when it is lower (near dawn) it looks darker. Now, I think it get it: I guess its because while the sky is still dark before dawn, the moon appears brighter, and that's how it looks in the image. But why is it that near dawn, not only does the moon appear less distinct, the clouds around the horizon also appear dark. i.e. There seems to be a conflict: When the moon is up high it should seem bright (and it does) but the sky should be dark (its not). By contrast, at dawn, the moon should be less distinct (it is) but only because its being viewed against a brighter sky (but in the image the horizon is dark).

The brightness of the Moon is not affected by the brightness of the sky. A bright sky only reduces the contrast between the sky and Moon. A nearly full Moon in daylight is exactly as bright as a nearly full Moon at night.

The reason the Moon appears brighter in this image at higher altitudes is because it is brighter at higher altitudes. Atmospheric extinction increases dramatically near the horizon, where you are looking through several times more air. This is why you can often look directly at the setting Sun.

The sky itself appears nearly the same brightness everywhere because the image is a composite of the sky at the time of each subexposure. The exposures near dawn are providing most of the signal.

[alphachapmtl]

I liked today's APOD! I'm glad our planet has a moon.

It's also nice that moon has a planet.

[StarCuriousAero]

I've always dreamed of going here some day... this picture almost makes the waiting painful though...

Thanks to neufer for sharing the youtube link! I've always loved the original, didn't know there was a "boy" version as well. Guess I've learned my new thing for the day.

[NoelC]

What a stunningly beautiful composition!!!

Just goofing around with Google Maps street views, it looks as though the image must have been taken from somewhere around here.

-Noel

[mexhunter]

WOW! it is really a beautiful composition.
Greetings
César