When those conditions are just right, the Earth, sun, and moon line up. This diagram shows how that looks: Then, if you're in the path of totality — which is basically the center of the moon's ...

In contrast, during a total solar eclipse — which is preceded by a partial eclipse — the moon completely covers the sun, ...

Elongation is the angle, in degrees, between the Sun and the planet as seen from here on the Earth. Superior planets (those that lie further from the Sun than us: Mars, Jupiter, Saturn, Uranus, ...