Changing Position of the Planets in the Night Sky

Understanding the Motion of Planets

The planets in our solar system orbit the Sun, and as a result, they appear to move across the night sky.
The speed and direction of a planet’s motion depends on its distance from the Sun. Farther planets move more slowly because they have a longer distance to orbit.
The apparent motion of the planets is also influenced by the motion of the Earth around the Sun.

Sometimes, planets appear to change direction against the stars, a phenomenon known as retrograde motion.
Retrograde motion occurs when the Earth, which orbits the Sun more quickly than outer planets (Mars, Jupiter, Saturn etc.), catches up with and passes an outer planet.
From Earth, the outer planet appears to move backwards in the sky. This backwards shift is the retrograde motion.
Even though the planet is still moving forward in its orbit, the relative speeds of Earth and the outer planet make it seem as if the planet is moving backwards.

The exact position of a planet in the night sky changes constantly and depends on both the planet’s orbit and the Earth’s orbit.
Night Sky Diagrams, also known as Star Charts, can be used to locate and identify the position of planets.
Planetarium software and mobile apps provide real time tracking and location of planets.

The best time to observe a planet is during its opposition, when it is opposite the Sun in the sky. It’s closest to Earth and fully illuminated by the Sun during this phase.
Planets closer to the Sun, like Venus and Mercury, can often be seen shortly after sunset or before sunrise - they are known as Morning and Evening stars respectively.
The planets mostly move along an arc known as the ecliptic plane, which represents the path of the Sun across the sky.
With the naked eye, planets can be identified as they do not twinkle like stars. This steady light aids in distinguishing them from stars.

Always take care not to confuse bright stars (especially Sirius) and other celestial objects with planets.
It is critical to never observe the Sun directly without proper solar filters, as this can cause severe eye damage.
Weather and light pollution may impair the visibility during observation.