Astro Bob: See 5 planets line up after sunset
Five planets form a line in the western sky the next few nights. Here's how to find them.
Planets are like kids. They like running around. And when you get a group of them together they turn into a force of nature. This week five of the planets will gather in the western sky shortly after sundown and compel some people to look up. If you're one of them, read on.
Timing and location are important. You'll need a place with an unobstructed view to the west and to be out watching between 25 and 40 minutes after sunset. If you arrive an hour after sunset, Mercury and Jupiter will have set already. Find your local sunset time with timeanddate.com/sun and plan accordingly. For many of us, the sun goes down around 7:30, so 8 p.m. is a good ballpark estimate of when to watch. Also, be sure to bring binoculars.
Now face west. Venus should be obvious about 30 degrees (three fists) high straight in front of you. Compared to the other planets it's a brilliant bull's-eye. Next, take your binoculars and carefully focus Venus to a point. Then put the planet off to the left side of the center of view and slowly lower the binoculars towards the horizon. Just before you "hit bottom" you should see two "stars" fighting the bright glow of twilight. The lower one is Jupiter and the upper one Mercury.
On March 28, they'll be just 1.5 degrees apart and fit in the same field of view. Jupiter is departing the evening sky, while Mercury is just now entering it. By early April it will much easier to see when it climbs higher above the horizon.
Let's see. That's three planets. Time to take a break and wait for the sky to darken. Starting around 8:30-9 p.m. (in late twilight) find dazzling Venus again. Then tilt your head back and look five fists above and left of the planet to spot reddish Mars. On Tuesday night, March 28, the half-moon will make itself useful and guide you directly to the Red Planet — Mars sits just a few degrees below and right of the moon.
Just as the moon helped us find Mars, Venus will guide us to Uranus. But you'll need to know exactly where to look so you can tell the planet apart from several similarly bright stars nearby. From March 28-31, Uranus and Venus will appear together in the same binocular field of view. Just aim and focus on Venus, and use the map to pinpoint Uranus. On March 28, Venus and Uranus are 2.5 degrees apart. Their separation shrinks to a minimum of 1.2 degrees on March 30 and then increases to 2 degrees on March 31.
Uranus moves up and to the east during this time just like Venus but because it's almost 2 billion miles (3 billion km) away, it barely budges from a binocular standpoint.
While you'll have to do spread your observing over two shifts — one shortly after sunset and another during late twilight — I'm confident that with clear skies you'll see all five of the planets playing their favorite game — hide-and-seek.