Five Planets and the Moon in the Sky Tonight!

Look up 30 minutes after sunset this week, and you can find Mercury, Venus, Jupiter, Mars, Saturn, and the Moon spanning the sky. All five visible planets will not be in the sky together again until October of 2018.

8:30 PM, Mercury, Venus and Jupiter will be low in the west. Image: Stellarium and Me

It will be hard to see the planets in the west, because they are very low to the horizon. They may get lost in the setting Sun's glare, or be covered by trees or buildings. If you would like to see the conjunction, pick a location with a clear view of the western horizon, and visit it on the next clear night!

With buildings in the way, it will be difficult to see the western planets. Mars and Saturn will be easily visible in the south.

 By the end of the week, Venus and Mercury will be very low and difficult to see. 

By Sunday, Mercury and Venus will be very low and hard to see.

There was a very nice showing of all five planets visible to the naked eye in January of this year. Just like then, the alignment of the planets is due to their position relative to the Earth. Earth and Mercury, Venus, Mars, Jupiter and Saturn are all on the same side of the Sun right now. Just after sunset, when it is starting to get dark on Earth, we can see sunlight reflecting off the planets, making them appear very bright in our sky. 

Notice Mercury, Venus, Mars, Jupiter, and Saturn are all grouped together on the same side of the Sun, relative to Earth. Image Source: Solar System Scope

Watching the motion of the orbiting planets against the backdrop of the stars can be fun, and can help you track the passage of time, just like ancient astronomers did. As August progresses, you can watch Mars move closer to Saturn by tracking it against the stars in Scorpius.

Tonight, Mars will be to the right and below Saturn. 

In a week, Mars will be below Saturn.

In two weeks, Mars will be to the left of Saturn.

In three weeks, Mars will be quite a ways to the left of Saturn. 

As you follow the motions of Mars, you are watching the planet orbit the Sun! Mars takes just about two Earth years to complete one orbit, while Saturn takes about 30 years. Mars moves much more quickly against the backdrop of the stars than Saturn does. 

Good luck finding all five naked-eye planets this week! If you miss the western planets, enjoy Mars and Saturn all summer long. Don't forget, you can always learn what's up in the night sky in the Dome Planetarium at the Peoria Riverfront Museum, where we teach about space and science everyday. Follow us on Facebook or Twitter for daily updates! 

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