What is Elongation?

In astronomy, a planet's elongation is the angular separation between the sun and the planet, with earth as the reference point.

The greatest elongation of any given inferior planet occurs when said planet's position, in its orbital path around the Sun is at tangent to the observer on Earth.

The greatest elongation possible for the two inferior planets is about 48°.

Elongation is the angel observed from the Earth between the direction to the Sun and the direction to a planet.

The farther a planet lies from the Sun, the slower it moves around it.

While the Earth is an inferior plant, it is also a superior planet because of the interchange in its synodic period.

THE ELONGATION ISSUE

This issue's theme is elongation because the Earth is currently orbiting at 1.00 AU (Astronomical Unit) from the Sun, which places it somewhere around 25.8° east.

A Fun Fact:

Planets all shine by reflected sunlight, so half a planet is always sunlit while the other half is dark.

When an inferior plant is visible after sunset, it is near its greatest eastern elongation, however when it is visible before sunrise, it is near its greatest western elongation.

The greatest elongations of a planet happen periodically. The period depends on the relative angular velocity to Earth and the planet, as seen from the Sun.

The same cannot be said of Superior planets and asteroids. After conjunction, their elongation continues to increase until it approaches a maximum value larger than 90°. This is impossible for inferior planets.

Elongations may sometimes refer to the angular distance of a moon of another planet from its central planet.

Terms:
Inferior planets: Those planets that lie closer to the Sun than the Earth (Mercury and Venus).

Superior planets: Those planets that lie further from the Sun than the Earth

Conjunction: An elongation of 0°. An inferior conjunction occurs when the planet lies between the Earth and the Sun. A superior conjunction occurs when the planet lies on the opposite side of the Sun to the Earth.

Quadrature: An elongation of 90°. A planet can either be at an eastern or western quadrature.

Written by WordSmith001