Why does the crescent-shape of the Moon vary around the Earth?

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Offline mrsmith2211

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Maybe I just never paid attention enough, but the crescent is near the bottom of the moon tonight, Had some friends send sme pics from Guatamala, and the crescent appears to be on the opposite side in the southern hemisphere. Any good sites to eplain all this?
« Last Edit: 15/01/2016 08:15:34 by chris »

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Offline Colin2B

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Maybe I just never paid attention enough, but the crescent is near the bottom of the moon tonight, Had some friends send sme pics from Guatamala, and the crescent appears to be on the opposite side in the southern hemisphere. Any good sites to eplain all this?
It's all to do with orientation.
Hold a football (the earth) in your hand and imagine you standing on top of it looking at an object on the other side of the room.
Now imagine yourself on the opposite side - bottom - of the ball, the object will appear upside down because you are now the other way up, it's as if you were standing on your head!
and the misguided shall lead the gullible,
the feebleminded have inherited the earth.

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Offline chris

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Maybe I just never paid attention enough, but the crescent is near the bottom of the moon tonight, Had some friends send sme pics from Guatamala, and the crescent appears to be on the opposite side in the southern hemisphere. Any good sites to eplain all this?
It's all to do with orientation.
Hold a football (the earth) in your hand and imagine you standing on top of it looking at an object on the other side of the room.
Now imagine yourself on the opposite side - bottom - of the ball, the object will appear upside down because you are now the other way up, it's as if you were standing on your head!

Nice explanation! Thanks.
I never forget a face, but in your case I'll make an exception - Groucho Marx

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Offline RD

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In addition to being upside-down, there is also a slight parallax-effect : photos of the moon & stars taken simultaneously on earth won't be exactly the same because of the different viewpoints ...

[attachment=20782]
http://astrobob.areavoices.com/2013/07/15/half-moon-has-brush-with-spica-tonight-aurora-update/   [ Not to scale ]

Earth & Moon [to scale] ...


Parts of the limb of the moon visible from one location will not be visible from the other location, so the crescent will appear slightly different , even if the photos were taken at exactly the same moment.
« Last Edit: 16/01/2016 13:12:58 by RD »