Anyone has a picture of crescent moon under rainbow? I need such picture for science fair?

Answer 1

No one will have one, unless it was created in Photoshop.

Here's why.
When the moon is a crescent, either just after new moon or just before new moon, the Moon appears to be close to the Sun in the sky. At "new Moon" the Moon and Sun line up (the Moon eclipses the Sun when the lineup is perfect). Rainbows occur in the part of the sky opposite the sun. If you face the center of a rainbow, the sun will be behind you, as will the crescent Moon, which will be close to the Sun, so the crescent Moon cannot appear under a rainbow. The full Moon, however, can. AND always assuming that there are breaks in the clouds that allow the Moon to be seen, since without clouds and raindrops, no rainbow will be seen.

The highest that the top of a rainbow can be is about 53 degrees on the secondary or double rainbow and 42 degrees on the top of a single rainbow. This can occur only when the Sun is on the horizon. The center of the semicircle traced by a rainbow is 180 degrees away from the sun in hte sky. So, if the sun is more than 53 degrees above the horizon (about halfway to straight overhead), no rainbow can be seen. You never see a rainbow at noon, but only in the mornings or late afternoons. The first quarter Moon or last quarter Moon is only 90 degrees away from the sun, while the top of the "double" rainbow is 180 - 53 = 127 degrees away from the sun. The moon has to be more than 127 degrees away from the sun in order to be inside a rainbow,. This corresponds to about 10 days after the new Moon or 10 days before the new Moon, OR the period from four days before the full Moon to four days after the full Moon.

Answer 2

Great answer, Dave. And Jack, did you just do that for this person? How nice!

Answer 3

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http://s226.photobucket.com/albums/dd11/jackphotos123/?action=view¤t=moon.jpg
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