What is a planet in opposition?

The best time to see and photograph a planet is when it is at 'opposition'. Find out more and check the key opposition dates for Mars, Jupiter, Saturn, Uranus and Neptune.

What is a planet in opposition?

Visit Insight Investment Astronomy Photographer of the Year

All the planets in the Solar System orbit around the Sun. At certain points during these orbits, the Earth finds itself directly between the Sun and another planet. This is the moment at which that planet is said to be 'in opposition'. 

When Saturn is in opposition for example, Earth is between the Sun and Saturn. From our vantage point on Earth, Saturn is on the 'opposite' side of the sky to the Sun: when the Sun sets in the west, Saturn appears in the east.

Saturn at opposition (NASA)
Saturn is 'at opposition' when the Earth is directly between the Sun and Saturn (diagram courtesy of NASA)

Only planets that are further out in the Solar System than the Earth can be in opposition: Mars, Jupiter, Saturn, Uranus and Neptune. Because Venus and Mercury are closer to the Sun than the Earth, they can never be in opposition.

Why is a planet in opposition important?

Some of the best times to see planets in the night sky occur when they are at opposition. During opposition the planet appears at its largest and brightest, and it is above the horizon for much of the night. For stargazers and astrophotographers, it's an ideal time to view and photograph the superior planets.

Planets, Comets and Asteroids: Insight Investment Astronomy Photographer of the Year 2019 winners

Family portrait - The King and his court © Jordi Delpeix Borrell
Family portrait - The King and his court (© Jordi Delpeix Borrell, Insight Investment Astronomy Photographer of the Year 2019)

How to photograph a planet in opposition

"If you really want to get the best photo of a planet you want to try and aim for when it’s riding really high in the sky and ‘at opposition’," explains Steve Marsh, Insight Investment Astronomy Photographer of the Year judge and BBC Sky at Night Magazine art editor.

"You want the air to be nice and still," he adds. "If you can get all those three things combined then you are going to have a really great picture at the end of it."

For more information about how to photograph planets in opposition, watch the video above featuring Steve and images from the Insight Investment Astronomy Photographer of the Year exhibition.

See stunning space photos at Insight Investment Astronomy Photographer of the Year

Planet opposition dates

Planetary oppositions for Jupiter, Saturn, Uranus and Neptune occur almost every year, as Earth on its much faster orbit passes between these planets and the Sun.

Mars is slightly different: because Earth and Mars are relatively close together in the Solar System, an opposition of Mars happens roughly every 27 months.

Planets in opposition 2019
Date Planet
10 June Jupiter
9 July Saturn
9 September Neptune
27 October Uranus

 

Planets in opposition 2020
Date Planet
14 July Jupiter
20 July Saturn
11 September Neptune
13 October Mars
31 October Uranus

Main image: Infrared Saturn (© László Francsics, Insight Investment Astronomy Photographer of the Year 2019)