Skywatching: January 29-February 1
All the naked-eye planets are visible in the morning sky before sunrise.
You have probably heard the news reports about being able to see five planets at once. This doesn’t happen very often, but it also is not some kind of weird cosmic alignment. It just means that if you were to view the Solar System from far above, so you could see the planets in their roughly circular orbits, you would see Mercury, Venus, Earth, Mars, Jupiter, and Saturn on the same side of the Sun. In other words, if the whole Solar System were a pizza with the Sun in the middle, those six planets would be somewhere on the same half of the pizza.
Because Mercury is never far away from the Sun, this weekend presents the best opportunity to see all five planets due to the fact that Mercury is about to reach its greatest separation from the Sun (as seen from Earth). Weather permitting, wake up before 6:00 am CST and find a location with an unobstructed view of the eastern horizon. If you are in the Chicago area, a convenient spot is the shore of Lake Michigan.
Jupiter will be easy to find. Turn away from the eastern horizon (Lake Michigan) and look in the southwest. Jupiter will be the brightest object in the sky, about a third of the way up from the horizon. Now start scanning back toward the east. The next bright light you will see as you scan left from Jupiter is the star Spica. Keep scanning left (eastward) and the next bright light you will see is Mars. Mars has a distinct orange color compared to the blue color of the star Spica and the white color of Jupiter. Mars is currently much dimmer than Jupiter, and it won’t be twinkling like Spica will be.
Keep scanning leftward and downward toward the horizon and you will next run into two more orange-yellow lights. One is the planet Saturn and the other is the star Antares. Antares will be closer to the horizon and will be twinkling. Saturn will not.
Now things get a little trickier. Venus is impossibly bright, but it does not rise until about 5:15 am Central time. If you have any obstruction on the eastern horizon, however, you may not be able to see it until 5:45 am or even later. By 6:00 am it will be far enough above the horizon, low buildings, and trees that you can’t miss it. You might be fooled into thinking it is an airplane. But if it doesn’t move, it’s Venus.
Now you are racing the clock. Mercury probably won’t be high enough above the horizon until about 6:15 am. Scan the horizon before that, however, as your seeing conditions may allow you to find it. It will be much, much dimmer than Venus. Look for a small but steadily shining point of light below and to the left of Venus. I’ve been fooled many times to thinking that I saw Mercury only to realize it was a far off airplane. Your challenge is to find Mercury before the dawn twilight brightens so much as to make the tiny planet disappear in the glow of the soon-to-be-rising Sun.
Good luck, and take a look at the diagram I’ve included in this post. It is from Sky and Telescope.