March Brings Cluster of Planets Into View

Early in March, the planets Mars, Mercury, Neptune and Jupiter are clustered in the constellation Capricorn in the morning twilight. They are spread along the east-northeast horizon.

Jupiter is conspicuous at magnitude -2.0. Mercury shines at -0.1 at the beginning of March, brightening as it dips toward the horizon through the month to 0.9, then becoming lost in the glare of the sun. Mars remains at magnitude 1.2, moving along with Neptune (very hard to spot in the twilight at magnitude 8) into the constellation Aquarius by month's end.

On March 1, Mercury and Mars lie within about a half degree. About 6:30 a.m. on March 23, you may be able to spot Neptune a half degree below the slim crescent of the moon.

Saturn remains in Leo all month, at magnitude 0.5. The rings are almost edge-on from our perspective here on Earth. The rings only are about 100 to 300 yards thick and are difficult to spot now without a large telescope. This 173,000-mile-wide band of mostly ice crystals will appear mainly edge-on until about March 2011.

Venus remains an evening planet at a brilliant -4.5 magnitude, slowly dropping toward the horizon through the month, eventually becoming lost in the sun's glare. The waxing crescent moon is within a degree of the Pleiades in the early morning hours March 3, and again on March 30.

The largest asteroid, Ceres, can be spotted about 20 degrees north of Saturn throughout March. If Ceres were to sit upon the United States, it would spread over 600 miles — the distance from Canton to Memphis. It is unusually bright at magnitude 6.9, and with good eyesight and clear, dark skies can be seen with the unaided eye.

When first found, Ceres was deemed a planet, until many other objects were discovered in the area between Mars and Jupiter. This area was then designated the Asteroid Belt, with Ceres as the largest asteroid. With the recent debate about the status of Pluto, Ceres almost became a planet again, but ended up with the status of ''dwarf planet.''

The spring, or vernal, equinox occurs on March 20, heralding spring. Remember to set your clocks ahead on March 8, as daylight saving time begins.