April 2002

By Steve Stefanik

Five planets, Jupiter, Saturn, Mars, Venus, and Mercury are visible this April (in that order from highest to lowest) facing west after the sun sets. Although they currently span more than 40 degrees, this is the beginning of the best planetary conjunction in almost two decades. They will continue to close in on one another in the weeks and months ahead.

Jupiter is the highest of the planets and only second in brightness to Venus at magnitude –2.2. It is 27 degrees east of Saturn near the two brightest stars Castor and Pollux in the constellation Gemini.

Saturn remains near the bright first magnitude star, Aldebaran, in the constellation Taurus. Although they are similar in color, Saturn is almost twice as bright at +0.1 magnitude.

Mars is the dimmest of the five at +1.5 magnitude and merely a red-orange speck. It is just to the left of the Pleiades open star cluster in nearby Taurus.

Venus is fourth in line and the brightest of the planets at –3.9 magnitude. It hovers low in the west-northwest at dusk but gets a little higher with each passing week.

Mercury is last in line and last to appear in the second half of the month. You may not be able to see it until mid-April when it will be 13 degrees lower and to the right of Venus but you’ve got to be quick because it sets within an hour after the sun goes down. It remains in view more than 1 ½ hours after sunset and within 6 degrees of Venus by the end of the month.

Although Jupiter remains relatively distant from the other planets, the gap between Saturn and Mars shrinks from 19 degrees to less than 3 degrees and the gap between Mars and Venus diminishes from 21 degrees to 5 degrees with only 8 degrees separating the middle three planets.

Don’t forget to turn your clocks ahead one hour in observance of Daylight Savings Time if you haven’t done so.