Five visible planets in alignment this August

July 14, 2016, Swinburne University of Technology

This August, stargazers will have a rare opportunity to see five visible planets in the night sky at the same time with the naked eye.

From Earth we will be able to see Mercury, Venus, Mars, Jupiter and Saturn trace a line on the sky away from the setting Sun.

Earlier this year we could catch this arrangement in the pre-dawn morning. This time it is in the evening, and it will be the last chance to see this phenomenon until October 2018.

For those near the equator, the trace a line directly vertical from the overhead. As you move towards the poles – towards North America or Australia – the line the planets trace tilts lower towards the horizon.

Swinburne University of Technology astronomer Dr Alan Duffy says that anyone in the world will be able to see this event without requiring a telescope or binoculars.

"The fainter planets that lie closer to the Sun, such as Mercury and Venus, will be difficult to see so it is best to wait until after sunset for the twilight to fully fade, but before the planets set," Dr Duffy says.

"The planets stretch across the sky, anchored to the horizon following the setting Sun. This is because the entire Solar System is flat like an old vinyl record with the planets moving along these grooves of the record. Looking out from the Earth we will see this as a straight line, known as the ecliptic plane, tracing across the sky.

"The further north or south you are from the equator, the closer to the horizon this line will be giving you less time after sunset to clearly spot Mercury in particular. Some planets don't orbit perfectly on the vinyl record, meaning they appear a little off the ecliptic plane so tend to form triangle shapes with each other as they pass by from our point of view such as Mercury, Venus and Jupiter later in August.

"The challenge with this event is to get the timing right to ensure the sunset has faded as much as possible but not wait so long that Venus or Mercury have raced below the horizon.

"For Australia it's best to look west by 7pm towards the end of August.

"If you're in Europe or North America you need to wait later for the Sun to set around 9pm. Even then, the further you are from the equator the less time you'll have before the planets appear to vanish beneath the horizon.

"The best time to look is either side of the Full Moon on 18 August as the light from the Moon washes out the fainter planets. The hardest planets to spot will be those fainter ones close to the horizon, so make sure to find somewhere dark with as clear a view as possible to the west where the Sun has set, meaning no low lying buildings or trees," Dr Duffy says.

"The event this year is your last chance to see all the visible planets together in the same until 2018. It's a reminder of the size of the Solar System that these stretching over enormous distances appear to us no more than delicate lights strung across the sky."

Explore further: All five bright planets come together in the morning sky

Related Stories

All five bright planets come together in the morning sky

January 15, 2016

For the first time in more than 10 years, it will be possible to see all five bright planets together in the sky. Around an hour or so before sunrise, Mercury, Venus, Mars, Jupiter and Saturn, the five planets that have been ...

Dance of the planets in the evening sky

February 19, 2015

Armagh Observatory reports that the next two weeks provide a rare opportunity to observe the planets Venus, Mars and Uranus in the western evening sky after sunset, and the bright planet Jupiter rising high in the East about ...

Close approach of Venus and Jupiter visible in evening sky

June 15, 2015

Armagh Observatory reports that the next two weeks will provide an interesting opportunity to observe the brightest planet, Venus, and the largest planet, Jupiter, as they move towards one another in the evening twilight.

Recommended for you

EPA adviser is promoting harmful ideas, scientists say

March 22, 2019

The Trump administration's reliance on industry-funded environmental specialists is again coming under fire, this time by researchers who say that Louis Anthony "Tony" Cox Jr., who leads a key Environmental Protection Agency ...

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.