SKYWATCH

March 1997

by Steve Stefanik

The old saying related to the month of March, "in like a lion, out like a lamb" is applicable this year not only with regard to the weather, but also as it pertains to astronomical events.

Comet Hale-Bopp is bearing down on us and will come within 1.31 astronomical units from Earth (1 a.u. is equal to the distance from Earth to the sun). It is presently in the northeastern early morning sky before dawn just below the brightest star Deneb in the constellation Cygnus (the Northern Cross). Currently it is about second magnitude, somewhat dimmer than nearby Deneb but it is expected to brighten to at least first magnitude and possibly rival Sirius, the brightest star in the winter sky. It is touting a short five degree fan shaped tail which is standing straight up from the horizon away from the sun. By mid-month it will be about 30 degrees above the eastern horizon and by month’s end it will be visible in both the early morning northeastern sky and early evening northwestern sky not far from the Great Spiral Galaxy M31, in the constellation Andromeda. The tail should lengthen considerably as it approaches the sun on its way toward perihelion when it is closest to the sun on March 31st.

Not to be outdone, Mars is rising rapidly due to its retrograde (backwards) motion in the east about 7:30 p.m. EST in the constellation Virgo in the beginning of the month on its way toward opposition on the 17th, when it will be directly opposite us from the sun. It will rise at sunset, be due south at midnight, and set as the sun rises the following morning. It will be at its brightest -1.3 magnitude then. Even though it is almost as far as it ever gets from Earth during this opposition, it will be as high in the sky as it ever gets, some 58 degrees above the horizon, so we should have a pretty good view of its northern polar ice cap and some of its darker mountainous regions and lighter desert areas through a telescope.

Mars will be within 10 degrees of an almost fully eclipsed full moon on the night of the 23rd. It should make for a dramatic view as the red planet compliments the red hue of a 92% covered lunar surface. The moon will begin slipping into Earth’s umbra (the darkest part of the shadow) by 10:00 p.m. EST. The maximum amount of the moon will be covered by 11:30 or so and will be uncovered again by 1:20 a.m. the following morning. This will be the last lunar eclipse until the year 2000.

Those of you who are anxiously awaiting Spring, won’t have to wait much longer. It officially arrives at 8:55 a.m. EST (when the sun traveling along the ecliptic crosses the celestial equator), on March 20th when the sun rises due east on that date. The Christian holiday of Easter will be celebrated this month on the first Sunday after the first full moon after the Vernal Equinox which occurs on March 30th this year.

Early March is also the last month to get a view of the ringed planet Saturn before it is in conjunction with the sun on March 30. It won’t be seen again until late April when it rises early in the morning before sunrise in the east.

Mercury makes its return to the western sky by mid-March. The fleet-footed planet puts on its best show for 1997. Start scanning the western horizon about an hour after sunset for a -0.6 magnitude star-like object. Through binoculars you will notice that it will be in a gibbous phase like our moon is between first and last quarters.

Venus is behind the sun this month. Pluto, Uranus, and Neptune rise in the east in the wee hours of the morning.