Last modified: Tuesday, March 1, 2005
Saturn and Jupiter compete for attention in March
BLOOMINGTON, Ind. -- Saturn and Jupiter will compete for attention on clear nights in March.
Saturn will be high in the south at nightfall, perfectly placed for viewing with a telescope. The bright yellow planet will be in the constellation Gemini the Twins, high above the familiar bright stars of the constellation Orion the Hunter. See http://saturn.jpl.nasa.gov/home/index.cfm for the latest news and images from the Cassini spacecraft that is orbiting Saturn.
The line of three bright stars in Orion's belt always points almost directly to Sirius to the left (east). Sirius is the brightest actual star in the sky of the Northern Hemisphere. If you watch Sirius carefully on a clear dark night, you can see it twinkle in different colors in addition to its usual brilliant white.
In the other direction, the line of Orion's belt points upper right (west) toward the bright orange star Aldebaran. Keep going on the same line past Aldebaran and you'll reach the Pleiades star cluster, a beautiful sight in binoculars.
Jupiter, the largest planet and second only to Venus in brightness, will rise earlier each evening in March. It will appear low in the east-southeast around 9 p.m. local time at the beginning of the month and right after sunset by month's end. Jupiter will be opposite the sun and closest to Earth early next month.
Mercury will make one of its best evening appearances of the year, at first coming into view close to the western horizon and setting an hour after sunset. The small planet will quickly move higher as the days pass, reaching its greatest elevation on March 12. Then it will plunge back toward the sun, disappearing into the solar glare by the end of the third week and passing between Earth and the sun on March 29.
Mars, where the Spirit and Opportunity rovers continue to explore, will appear as a faint orange dot low in the southeast, rising around 4 a.m. local time at the start of March and an hour earlier at month's end.
Venus will be out of sight as it passes behind the sun during March.
On March 3 before dawn, the third-quarter moon will pass in front of the bright orange star Antares (pronounced an-TAR-eez) in the southeastern sky, an event called an occultation. The event will be visible in most of western and central North America, but sunrise will overpower it before viewers farther east have a chance to see it. Antares will slowly approach the bright edge of the moon, disappear for about an hour, and then pop back into view from behind the moon's opposite dark edge. This sudden reappearance of a bright star in a dark sky is what makes an occultation fun to watch.
Details of the event are available at http://skyandtelescope.com/observing/objects/occultations/, including a map showing where the occultation will be visible and its exact time for various cities. For those watching in Indianapolis, for example, Antares will disappear behind the moon's bright edge at 5:45 a.m. EST and suddenly reappear on the dark edge at 7:07 a.m. Binoculars or a telescope will give a better view as the morning sky brightens, but in a dark sky the event will be easily visible to the unaided eye.
The sun will cross the celestial equator (an extension of Earth's equator onto the sky) on March 20 at 7:33 a.m. EST (12:33 Universal Time) heading north. The March equinox marks the start of spring in the Northern Hemisphere and fall in the Southern Hemisphere. For the next six months in the Northern Hemisphere, the days will be longer than the nights.
Followers of many religious faiths around the world observe days of celebration during March and April as spring returns to the Northern Hemisphere. Most of these days are linked in some way to the March equinox. For example, each year Easter falls on the first Sunday after the first full moon after March 20, the most common date of the equinox.
Day and night are not precisely the same length at the time of the equinox. That happens on different dates for different latitudes. At higher latitudes in the Northern Hemisphere, the date of equal day and night occurs before the March equinox. In the Southern Hemisphere, this happens after the March equinox. Information about exactly when the equinox happens at different places on Earth's surface is provided by the U.S. Naval Observatory at http://aa.usno.navy.mil/faq/docs/equinoxes.html.
The moon will be at third quarter on March 3, new on March 10, at first quarter on March 17 and full on March 25.