where would someone on Earth have to be located to see a last quarter moon directly overhead?

Answer 1

Outside.

Answer 2

You'd need to be directly beneath the last quarter moon.

The next last quarter moon will occur on 2007 Nov 12 @ 17:45 UT according to Sky & Telescope. You can also find this information at the US Naval Observatory website.

If you go to this website and ask for the position of the moon at that time:
http://aa.usno.navy.mil/data/docs/geocentric.html

You find that it will be at: Right Ascension = 9h 34m 9.303s and Declination=17 degrees 26 minutes 22.25 seconds declination.

That means the location on earth that is directly under the moon at that time will be on North Latitude = 17 degrees 26 minutes 22.25 seconds. The Longitude needs to be found by computing the sidereal time at Greenwich for 2007 Nov 12 @ 17:45, then subtract that from the Right Ascension we found above and multiply the difference by 15 to find the actual Longitude of that position.

Answer 3

Well, first they would have to be somewhere between 28 degrees north and 28 degrees south of the equator to EVER see the Moon directly over head (23 degrees for the tilt of Earth's axis, another 5 degrees since the Moon's orbit is tilted 5 degrees relative to the ecliptic). Exactly where depends on the time of year and where the Moon is in its orbit relative to the line of nodes.

Third (or last) quarter moon rises at midnight and sets at noon, so it would be at its highest in the sky at sunrise. So we can't say exactly *where* that person is, but we know *when* she is looking at the Moon.

Answer 4

The three answers given before me are all correct and compliment each other. Can the ten points be diivided between them?