APOD: Crescent Moon Meets Evening Star (2013 Sep 13)

[APOD Robot]

Crescent Moon Meets Evening Star

Explanation: On September 8, brilliant planet Venus appearing as the evening star stood near a slender, crescent Moon at sunset. The close celestial pairing or conjunction was a scene enjoyed by skygazers around the world. But from some locations in South America, the Moon actually passed in front of Venus in a lunar occultation. Captured near Las Cañas, Uruguay, this two frame mosaic telescopic view shows the Moon and Venus before and after the occultation. The silvery evening star appears at right just before it winked out behind the dark lunar limb, still in bright twilight skies. About an hour later Venus emerged (left) along the three day old Moon's sunlit edge.

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[geckzilla]

If a transit is a mini-eclipse, is an occultation a mega-eclipse?

[Guest]

This picture threw me for a loop - just for a minute! Three day old crescent moon? Forming the shape of a C while it's still waxing? Whatever happened to Luna Mendox?

Luna Mendox is Latin for "The Moon is a Liar": it always forms the shape of a D while it is waxing (Crescens), and it forms the shape of a C while it is waning (Decrescens). And here's the Moon being truthful!

Then I realized - oh, Uruguay. I'd never thought about it, but in the southern hemisphere the C and D shapes would be reversed.

Luna Veracem.

Eric

[Boomer12k]

Neat....

:---[===] *

[neufer]

If a transit is a mini-eclipse, is an occultation a mega-eclipse?

Probably a maxi-eclipse. (Mega is the opposite of micro.)

[neufer]

Click to play embedded YouTube video.

[c]To be in Carolina in the morning[/c].

This picture threw me for a loop - just for a minute! Three day old crescent moon? Forming the shape of a C while it's still waxing? Whatever happened to Luna Mendox?

Luna Mendox is Latin for "The Moon is a Liar": it always forms the shape of a D while it is waxing (Crescens), and it forms the shape of a C while it is waning (Decrescens). And here's the Moon being truthful!

Then I realized - oh, Uruguay. I'd never thought about it, but in the southern hemisphere the C and D shapes would be reversed.

Luna Veracem.

[MadMan]

Thanks Guest! I was stuck on a similar question: why was the Moon moving to the right past Venus instead of to the left? Same answer: southern hemisphere.

[EvilKirk]

But what of Lazarus? What of Lazarus?

[jlw]

Not withstanding the comments and explainations above, I believe this photo is up-side-down. Whether north or south of the equator, the moon still transits the background stars from west to east. Being an evening event, Venus would first be visible in front of (east of) the moon and exit behind (or west) of the moon. This picture would make more sense if inverted.

[walker1001]

Crescent Moon Meets Evening Star

Explanation: On September 8, brilliant planet Venus appearing as the evening star stood near a slender, crescent Moon at sunset. The close celestial pairing or conjunction was a scene enjoyed by skygazers around the world. But from some locations in South America, the Moon actually passed in front of Venus in a lunar occultation. Captured near Las Cañas, Uruguay, this two frame mosaic telescopic view shows the Moon and Venus before and after the occultation. The silvery evening star appears at right just before it winked out behind the dark lunar limb, still in bright twilight skies. About an hour later Venus emerged (left) along the three day old Moon's sunlit edge.

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This Day in APOD

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[/b]

In the picture description right and left are reversed. If they don't get it right we could be left with difficulties in other pictures. Luckily this one is so easy to see that we are left with no doubt how to put things right.

[walker1001]

Not withstanding the comments and explainations above, I believe this photo is up-side-down. Whether north or south of the equator, the moon still transits the background stars from west to east. Being an evening event, Venus would first be visible in front of (east of) the moon and exit behind (or west) of the moon. This picture would make more sense if inverted.

And that way everything would be put right and not left[/i in a mess.Right??

[geckzilla]

Not withstanding the comments and explainations above, I believe this photo is up-side-down. Whether north or south of the equator, the moon still transits the background stars from west to east. Being an evening event, Venus would first be visible in front of (east of) the moon and exit behind (or west) of the moon. This picture would make more sense if inverted.

Would it? Here is a simulated view of the moon, including the horizon, as viewed from Uruguay after Venus has emerged from behind the moon. The red line is the orbital path of Venus.

In the picture description right and left are reversed. If they don't get it right we could be left with difficulties in other pictures. Luckily this one is so easy to see that we are left with no doubt how to put things right.

Are you sure about that? The description seems correct to me.

[geckzilla]

If a transit is a mini-eclipse, is an occultation a mega-eclipse?

Probably a maxi-eclipse. (Mega is the opposite of micro.)

Mega sounds better, though. Maxi reminds me too much of feminine hygiene products.

[neufer]

If a transit is a mini-eclipse, is an occultation a mega-eclipse?

Probably a maxi-eclipse. (Mega is the opposite of micro.)

Mega sounds better, though. Maxi reminds me too much of feminine hygiene products.

How about a midi-eclipse then

Microskirt

Miniskirt, a thigh-length skirt, and micromini, an extremely short version (1960s)

Midi skirt, mid-calf length. 1970

Maxiskirt, an ankle length-skirt (1970s, but has made a comeback in the 2000s)

[luigi]

Thinking about left and right in different hemispheres can get you dizzy.

Both the Moon and Venus set while moving to the left in the south hemisphere.
But the Moon apparently moves to the right with respect to the background stars.
So Venus seems to move from right to left if you take the Moon as a reference.

[BMAONE23]

If a transit is a mini-eclipse, is an occultation a mega-eclipse?

Probably a maxi-eclipse. (Mega is the opposite of micro.)

Not to pick nits but I thought that Macro was the opposite of Micro

[Beyond]

The 'Truth' is out there somewhere. It's just covered up by all those damn nits

[neufer]

If a transit is a mini-eclipse, is an occultation a mega-eclipse?

Probably a maxi-eclipse. (Mega is the opposite of micro.)

Not to pick nits but I thought that Macro was the opposite of Micro

• Just so long as the nits aren't too big.

<<Macrophilia refers to a fascination with or a sexual fantasy involving giants, or giantesses. While some fantasize about a giant who is slightly taller than himself, others are interested in giants that are hundreds or even thousands of feet tall.>>

<<Brobdingnag is the land in Jonathan Swift's satirical novel Gulliver's Travels occupied by giants. The people of Brobdingnag are described as giants who are as tall as a church steeple and whose stride is ten yards. All of the other animals and plants, and even natural features such as rivers and even hail, are in proportion. The rats are the size of large dogs and the flies are the size of birds, for example. This also means that the country is far more dangerous for people of normal human size, as evidenced by Gulliver using his hanger far more often here—namely, on attacking vermin. A splacknuck is an animal about 6 feet long, to which Gulliver is compared in size, although it is never explained which animal it corresponds to (probably a rodent of some sort, such as a rat). Brobdingnagian culture consists of history, poetry, mathematics and ethics, mathematics being a particular strength. Printing has been long known but libraries are relatively small. The king has the largest library, which contains about one thousand volumes. The Brobdingnagians favour a clear literary style.>>

[Anthony Barreiro]

Thinking about left and right in different hemispheres can get you dizzy.

Yes, it can. But it's fun.

Both the Moon and Venus set while moving to the left in the south hemisphere.
But the Moon apparently moves to the right with respect to the background stars.
So Venus seems to move from right to left if you take the Moon as a reference.

Thanks Luigi, your explanation is clear and helpful to me. It's also a bit dizzying to remember the relative motions of the Earth, Moon, and planets!

The first thing I noticed about this image was that the Moon appears "upside down" compared to how I usually see her in the sky, with Mare Crisium toward the bottom rather than the top. Then I read that the picture was taken in Uruguay and figured out that the northern limb of the Moon is toward the bottom as seen from the southern hemisphere, rather than toward the top as I see her from the northern hemisphere.

[walker1001]

In the picture description right and left are reversed. If they don't get it right we could be left with difficulties in other pictures. Luckily this one is so easy to see that we are left with no doubt how to put things right.

Are you sure about that? The description seems correct to me.[/quote]

You're quite right!!!

Memo to self: no "clever" posts when severely sleep-deprived.

[Diana]

Aaaand if they used a right-angle but had it turned to the right, or left side of the tube, would it the inverted image appear as moving in the wrong direction? I could mess with you some more on this, but no.

Diana

[DavidLeodis]

I'm not very good at picturing the change in view between the northern and southern hemispheres so I wonder how the occultation would have looked when seen from the Equator. Which way would Venus seem to move relative to the Moon? I'm

[Chris Peterson]

I'm not very good at picturing the change in view between the northern and southern hemispheres so I wonder how the occultation would have looked when seen from the Equator. Which way would Venus seem to move relative to the Moon? I'm :?

Occultations always move the same way, and they look the same from either hemisphere. The Moon moves eastward with respect to the background stars (and planets)... no matter which hemisphere you are in. The Moon has a north, south, east, and west limb, and they look the same no matter which hemisphere you are in. It is common to be facing south when viewing or photographing the Moon in the northern hemisphere, and north when doing so from the southern hemisphere. But there are common exceptions to that, especially when the Moon is near a horizon.

This is why terms like "left", "right", "above", and "below" are usually very poor choices when viewing astronomical images without referents for these relative concepts.

Regardless of which hemisphere you are in, an occultation when the Moon is near the eastern horizon will appear to reappear "above" the Moon. Near the western horizon, it will reappear "below" the Moon. For higher events, it will reappear "right" of the Moon if you are facing south, and "left" of the Moon if you are facing north. Instead of imagining how it might look while standing in a different hemisphere, imagine it from the perspective of lying on the ground, with your head in the same direction regardless of hemisphere.

[neufer]

I'm not very good at picturing the change in view between the northern and southern hemispheres so I wonder how the occultation would have looked when seen from the Equator. Which way would Venus seem to move relative to the Moon? I'm

Forget left/right for the moment.

The orbiting moon is always moving slowly (monthly) in the opposite direction
from its apparent daily motion (which is why tides come later each day).

Hence, the moon always rises slower than every thing else (including Venus)
and the moon also sets slower than every thing else (including Venus).

In the Northern Hemisphere the ecliptic passes to the South of one's head such that
the apparent daily motion of Sun, Moon and planets is from left to right.

In the Southern Hemisphere the ecliptic passes to the North of one's head such that
the apparent daily motion of Sun, Moon and planets is from right to left.

But the apparent daily motion of Moon is always slower than
the Sun, planets AND STARS regardless of where the Earthly observer is.

[DavidLeodis]

Thanks Chris and neufer for your help, which is appreciated.