Mar 19, 2004

A Gathering of Planets


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A Gathering of Planets

The five brightest planets are gathering in the evening sky for a rare after-dark display.





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March 19, 2004: Every few years or so, something wonderful happens: all five naked-eye planets appear in the evening sky at the same time. You can walk outside after dinner, and without any kind of telescope, see Mercury, Venus, Mars, Saturn, and Jupiter.


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Now is one of those times.


The show begins on March 22nd at sundown. Find a place where you can see the western horizon, and before the sky fades completely black, start looking for Mercury. It's that bright "star" shining through the rosy glow of the setting Sun. Can't find it? Use the Moon as a guide: On March 22nd Mercury will lie directly below the crescent Moon. Simple!

Right: Three planets and the Moon, photographed on April 6, 2000, by Robert Wielinga of the Netherlands. This month's display of five planets will be even better.

From Mercury, trace an imaginary line straight up. In order you'll see brilliant Venus, dimmer red Mars, and yellow Saturn. Behind your back hovers Jupiter, brighter than all the others except Venus.

Venus is, in fact, absurdly bright. It will be the first thing you notice when you go outside. Many people mistake glaring Venus for a UFO or a landing airplane, but if you watch for a few moments, you'll see it doesn't move or blink like a UFO or airplane. It really is a planet.

Venus is so bright that it can be seen in broad daylight--if you know where and when to look. March 24th is a good time to try, because the crescent Moon and Venus will be side by side. During the day, try scanning around the Moon using a pair of binoculars. When you find Venus it will seem to pop out of the blue--a pleasant surprise.

Be very careful, though, not to turn your binoculars toward the Sun. Sunlight focused through optics can fry your eyes.


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Above: Looking west just after sunset on March 24, 2004, as viewed from mid-northern latitudes. More sky maps:

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After sunset on March 24th, look west again. Mercury will be a little higher than it was on March 22nd, and thus easier to find. Trace the same imaginary line upward past Venus and the Moon (a dazzling pair), Mars, Saturn, and behind your back, Jupiter.

By now you've noticed that Mars is not so easy to find. Shining like a 2nd magnitude star, it is the dimmest of the five planets. On March 25th, however, you won't be able to miss Mars because it's going to be right beside the Moon. The pair will be even closer together than the Moon and Venus were the night before.




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The show continues on March 28th when the quarter Moon glides by Saturn, on March 29th when Mercury reaches its highest point in the evening sky, and April 2nd when the full Moon passes Jupiter. On any of these nights, try looking at the planets through a telescope. Even a small 'scope will reveal Saturn's rings, Jupiter's cloud belts and its largest moons, and the phases of Venus.

By the end of March, Mercury will be sinking back into the glare of the Sun, and soon thereafter the evening planet count will drop from five to four. Four is still a lot of planets. Jupiter, Saturn, Mars and Venus are going to be visible for months. In fact, they will gather even closer together in late April and May, and put on another wonderful show. But that's a story for another day.

Meanwhile, enjoy the five while they're there, so easy to see in the evening sky. It won't happen again until 2008.