Last modified: Friday, April 1, 2005
Jupiter at its brightest and a solar eclipse
BLOOMINGTON, Ind. -- Jupiter will be at its biggest and brightest during April, passing closest to Earth on the night of April 2-3. The giant planet will be opposite the sun in our sky that night, rising in the east soon after sunset, appearing highest in the south around midnight and setting in the west at dawn. This is the best time of the year to view Jupiter with a telescope. Its four largest moons, which Galileo discovered with one of the first telescopes, can be seen easily as well in a clear dark sky.
Wait until brilliant white Jupiter is high in the sky and then use binoculars to see its moons. These tiny bits of white light are strung out on both sides of the planet, and they seem to slide back and forth like beads on a string from one night to the next as they orbit the planet. You may need to steady the binoculars by resting your arms on a surface to keep the image from wobbling, but then you'll be able to see the moons. All four of them will be on the same side of Jupiter on the evenings of April 7 and April 21.
Saturn will be high in the west as darkness falls on April evenings, one of the first "stars" to appear. The bright yellow planet will still be an attractive sight in any telescope as it drifts through the constellation Gemini the Twins. A short distance above Saturn will be the two brightest stars of Gemini, Pollux on the left (south) and Castor on the right.
Mercury will have its poorest appearance of the year for viewers in the Northern Hemisphere during April, being visible barely above the eastern horizon less than an hour before sunrise in the last half of the month. In the Southern Hemisphere, however, observers will see Mercury before sunrise almost as high above the eastern horizon as it can ever get.
Mars will rise around 3 a.m. local time at the beginning of April and an hour earlier by month's end. The red planet is slowly coming closer to Earth, but it will take a few more months to become a suitable target for telescopes.
Venus will be out of sight as it passes behind the sun during April. At the end of the month it will reappear just above the west-northwest horizon shortly after sunset.
The crescent moon will be close to the Pleiades star cluster on April 11, a beautiful sight in binoculars. The Pleiades (pronounced PLEE-ah-deez) are lovely by themselves, and on a clear night they can be seen with the unaided eye in the constellation Taurus the Bull. A photograph of the Pleiades is available at http://antwrp.gsfc.nasa.gov/apod/ap021201.html and at several other Web sites as well.
Known prehistorically, the Pleiades were called the Seven Sisters in Greek mythology and other western legend. Many people in other parts of the world have stories about them as well. They are identified as a group of women in many cultures, from Australian Aborigine to Native American. To the Japanese their name is Subaru, from which the car's name was taken.
A partial eclipse of the sun will be visible in the Western Hemisphere on April 8. Daylight in the United States will not dim noticeably, but the eclipse will still be a fine sight for those who watch it safely. Staring at the bright sun can burn your retina, leaving a permanent blind spot in the center of your vision. Use a piece of number 14 welder's glass or an astronomer's solar filter. For details and a map of the path of the eclipse, including a list of times for various cities, see http://skyandtelescope.com/observing/objects/eclipses/article_1445_1.asp.
A total eclipse will be visible along a narrow path crossing the South Pacific Ocean, and an annular eclipse (a ring of sun completely surrounding the dark silhouette of the moon) will appear in parts of Costa Rica, Panama, Colombia and Venezuela. The eclipse will be partial across all of Central America and much of South America.
The Lyrid meteor shower will peak on the night of April 21-22. About 20 Lyrids per hour are normally visible, but this time the moon will obscure all but the brightest. The meteors can appear anywhere in the sky, but they will seem to come from a point called the radiant in the constellation Lyra the Harp, which gives the shower its name. Lyra's bright white star Vega will be almost at the radiant, and the meteor count should be highest when Vega is well above the eastern horizon, beginning around 11 p.m. local time in the Northern Hemisphere and lasting the rest of the night. The later the hour, the more meteors there will be.
A trio of bright white stars called the Summer Triangle is coming into view in the Northern Hemisphere, with Vega the first to rise each night in the east and leading the way high across the sky. The other stars are Altair in the constellation Aquila the Eagle to the south and Deneb in the constellation Cygnus the Swan to the north. When you are looking from Deneb to Altair, you are also looking at the Milky Way, though it is usually obscured by city lights. If you find a place that's dark enough for you to see the Milky Way, you'll also see a lot more meteors and other celestial objects from there.
The moon will be at third quarter on April 2, new on April 8, at first quarter on April 16 and full on April 24.