Question

What are the relative positions of the sun, Earth, and moon at the times of lunar and solar eclipses, as well as new, first-quarter, full, and last-quarter phases of the moon?

Answer 1

[1] New Moon: Earth, Moon and Sun lined up with the Moon coming between the Earth and the Sun. But usually the alignment is not perfect with the Moon's longitude lying a few degrees above or below the Sun's longitude. The Earth-Moon line and the Earth-Sun line are close to zero degree. However, occasionally the alignment could be near perfect leading to an eclipsing of Sun by the Moon. That is solar eclipse . Not every New Moon is a Solar Eclipse but every Solar Eclipse will coincide with New Moon. On New Moon days Moon rises along with the Sun.

[2] First Quarter: When the Earth-Moon line is `90^o` away from the Earth-Sun line, it is the First Quarter phase. On those days Moon rises (approximately) `6` hours after the Sun rise and exactly one quarter of the Moon's surface is visible from Earth.

[3] Full Moon: Moon, Earth and Sun lined up with the Earth coming between the Moon and the Sun. But usually the alignment is not perfect with the Moon's longitude lying a little above or below the Sun's longitude. The Earth-Moon line and the Earth-Sun line are close to `180^o` away. However, occasionally the alignment could be near perfect leading to an eclipsing of Moon by the Earth. That is Lunar Eclipse . Not every Full Moon is a Lunar Eclipse but every Full Moon coincides with a Full Moon. On Full Moon days Moon rises just as the Sun sets.

[4] Third Quarter: When the Earth-Moon line is `270^o` away from the Earth-Sun line, it is the Third Quarter phase. On these days Moon rises (approximately) 18 hours after the Sun rise or (approximately) `6` hours after the Sun set and again exactly one quarter of the Moon's surface is visible from Earth.