Planetary Alignment in the Predawn!

There is a show going on in the predawn sky. All five naked-eye planets are visible just before sunrise. Check the weather for clear skies and set your alarm when the forecast looks promising, because this chance alignment will last until about the first week in February. You only have to wake up by about 6:15 to catch the sight - late sunrises means easier predawn stargazing! Read on to learn how to find them. 

Mercury, Venus, Saturn, Mars and Jupiter are lined up in a row. They all rise at different times, but all five will be visible by about 6:15 until sunrise. Look to the southeast to find Mercury and Venus low on the horizon, and the rest of the planets stretch across the sky. See image below. 

Click on image to enlarge. Five plants are visible in a line from southeast to southwest in the predawn. Image Credit: Stellarium and Me. 

Jupiter rises at about 9:00 PM, Mars at about 1:30 AM, Saturn at about 4:30 AM, Venus at about 5:30 AM, and Mercury at about 6:15 AM. If you want to see all of the planets at once, your best bet will be at about 6:15 AM for the next several weeks. Try to find a viewing spots with a clear southeastern horizon. Buildings or trees in that direction will make finding Mercury difficult. Sunrise is getting earlier and earlier (and will continue to do so until the summer solstice) so the dawn light will start to obscure Mercury and Venus by about February 8. You have a good long time to catch this alignment - we are bound to have a clear morning one of these days!

So how will you know that you have found a planet? Well, most of the planets appear brighter than the stars nearby. Venus is the third brightest object you can see in the sky (behind the Sun and the Moon), because it is close, and covered in thick clouds that reflect a great deal of sunlight. Jupiter also appears quite bright, because it is so darn big. Mars will be noticeably red. Saturn and Mercury are less obvious, but if you find the other planets, the line they make will help you identify the trickier planets. Mercury is always the hardest planet to spot, because it is small, not very reflective, and often caught in the sun's glare. 

Look for the backwards question mark of Leo the Lion, or the fishing hook shape of Scorpius. Image Credit, Stellarium and Me. 

If you are up early, take a moment to look around and see what else you notice. The Moon will be visible, along the same line as the planets (more on that in a moment), and the summer and spring constellations will be up, giving you a taste of the season ahead! See if you can spot Leo the Lion or Scorpius the Scorpion. 

People often wonder at the pretty sight of the planets in such a neat line. The planets appear in our sky along the plane of the ecliptic, which is the Sun's apparent path through our sky. Of course the Earth moves around the Sun, not the other way around, but it looks like the Sun is moving through our sky day by day. This path of the Sun against the backdrop of the stars is called the ecliptic. Since all the planets orbit the Sun in a relatively flat plane, they all appear to follow that same path in our sky. And, since the Moon's orbit around the Earth is tilted only 5 degrees off of that plane, it appears roughly along the same path. 

A side view of the inner planets in our Solar System. Image Credit: Wikipedia Commons 

So why can we see all five of the planets visible without a telescope at once? Earth and Mercury, Venus, Mars, Jupiter and Saturn are all on the same side of the Sun right now. Just before sunrise, when it is still dark on Earth, we can see all five in the sky. Check out the current positions of the planets in their orbits in the below image. 

Notice where all the planets are compared to Earth. Click image to enlarge. Image Credit: Solar System Scope

Solar System Scope is a neat tool to play with. If you advance time, you can see that by mid February, Mercury and Venus have moved farther behind the Sun in their orbits, and the sun will be rising earlier on Earth, making those two planets impossible to see for a time, until they pass to the other side of the Sun and become evening objects. 

It is fun to watch the planets. If you make a habit of watching for them in the evening or morning, you will learn to use them to mark the passage of time, like the earliest astronomers who used the sky as their calendar. 

Good luck spotting the planets in the morning sky! It should be easy to find the brighter four, and Mercury will be a fun challenge. 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. Did you hear about the predicted (not proven) ninth planet in our Solar System? We will be teaching about it in our 3:00 PM show, Tour the Solar System!