" And of Joseph he said, Blessed of the LORD be his land, for the precious things of heaven, for the dew, and for the deep that coucheth beneath. And for the precious fruits brought forth by the sun, and for the precious things put forth by the moon." -- from the Blessing of Moses, Deut 33:13, 14
An eclipse of the Moon occurs at the time of a Full Moon. During most Full Moons, the Moon lies a little higher or lower than the Earth as compared to the Sun. So normally, the Sun's light shines fully onto the Moon's surface. But once in a while, the Full Moon lines up with the Earth and the Sun, and the Moon passes through the Earth's shadow. The Earth blocks the Sun's rays from falling on the Moon's surface, and the Moon grows dark for a time. And this is called a "Lunar Eclipse."
In Western history, the causes of the phases of the Moon and of lunar eclipses were first given by the Greek Pre-Socratic philosopher Anaxagoras, who flourished around 450 B.C. An historian named Aetius wrote of him:
"Anaxagoras, in agreement with the mathematicians, held that the moon's obscurations (phases), month by month, were due to its following the course of the sun by which it is illuminated, and that the eclipses of the moon were caused by its falling within the shadow of the earth, which then comes between the sun and the moon, while the eclipses of the sun where due to the interposition of the moon."
In about 350 B.C., The Greek philosopher Aristotle observed that the curved umbral shadow of the Earth on the Moon during a lunar eclipse was a proof that the Earth was in fact spherical. After all, what figure besides a spherical Earth could cast a curved shadow on the Moon?
"As it is, in its monthly phases the moon takes on all varieties of shape -- straight-edged, gibbous and concave -- but in eclipses the boundary is always convex. Thus, if eclipses are due to the interposition of the earth, the shape must be caused by its circumference, and the earth must be spherical."
-- De Caelo, Book II, Ch. 14
The Jewish historian Flavius Josephus records only a single lunar eclipse in his writings. King Herod had dispensed with two enemies both named Matthias. Josephus writes, "And that very night there was an eclipse of the moon." In a footnote, the translator points out that the rules of astronomy date this eclipse as March 13, 4 B.C. This fact helps date the death of Herod and helps establish the accepted traditional chronology of Jesus. This is another example of the practical usefulness of God's celestial order.
During the Age of Exploration, lunar eclipses had been used to determine the longitude of places far from home. Suppose a lunar eclipse was predicted to occur when the Moon was high in the sky from a location of known longitude. The same eclipse would also be seen as the Moon was rising somewhere far to the West. It would also be visible as setting somewhere far to the East. And anywhere in between, the Moon's position in the sky could be measured using an instrument such as a sextant. By comparing the Moon's measured position with its predicted position at home, a navigator could determine how far in longitude a ship was from home.