This month the Sun enters the astronomical sign of Pisces on the 12th and, on the 20th, the astrological sign of Aries. More than once I’ve been asked the question: How can the Sun be in two places at once? The answer is that Pisces is where it is now and Aries where it was in the far distant past.

This phenomenon has to do with precession, a term used to describe the wobbling of Earth on its axis of rotation much like a child’s top wobbles when it spins. Precession causes Earth’s axis to trace out a circle in the sky, thus making the Sun appear to be in a different place over time. It takes Earth, or Sun, nearly 26,000 years to complete one of these circles and, since there are 12 houses to the zodiac, more than 2,000 years to travel from one house to the next.

Close to the beginning of recorded history, some 6,000 years ago, the Sun was in Taurus at the vernal equinox. During the flowering of Greek civilization it moved into Aries and, around 100 B.C. into Pisces, where it remains today. Astrology had its birth when the vernal equinox was in Aries and continues to use that designation to the present day. That is why astronomers see the vernal equinox occurring in Pisces and astrologers in Aries.

By the way, an “Age” is named for the constellation in which the vernal equinox takes place. The Age of Aquarius, made famous in the musical “Hair” as ushering in universal peace and tranquility, is unfortunately a ways in the future. The vernal equinox will not take place in Aquarius until 2597 A.D.

Focus on the planets

Mercury opens the month low in the west after sunset. Look for Mercury well below a thin crescent moon on the 1st but, a week later, it will have vanished only to reappear in the southeastern predawn sky by month’s end.

Venus is very low in the southeast at dawn, where it is the brightest point of light in the sky, far outshining its planetary neighbor Jupiter.

Mars is high in the west at dusk in Taurus. Just to the upper right of Aldebaran early in the month, the red planet adds a second “red eye to the Bull.”

Jupiter rises in the southeast just before midnight as March opens and by 9 p.m. by month’s end. The best time to view Jupiter is during the predawn hours when it is well up on the horizon. The bright star to Jupiter’s lower left is Antares.

Saturn is high in the southeast at nightfall. Saturn’s rings are tilted for extremely favorable viewing and its many moons can be seen by telescope dancing around the planet. Its major moon, Titan, will orbit the ringed planet twice during the month and should be easy to identify.

Uranus is not visible during March.

Neptune may be spotted with strong binoculars or a telescope just below Venus in the southeast about an hour and a half before sunrise on March 26. The crescent moon lies well to the right, and slightly below, Neptune.

Pluto is in the south before dawn but likely is a lost cause for all but the most experienced viewers.

March events

1 Sunrise, 6:14 a.m.; sunset, 5:22 p.m. Look for Mercury well below the crescent moon in the west after sunset.

4 Mars and Aldebaran are the two reddish “stars” to the upper left of the moon tonight. Mars is to the upper right of Aldebaran.

5 Check out the sky this evening when the crescent moon lies between Mars and the Pleiades star cluster (M45) which is to the moon’s lower right.

6 Moon in first quarter, 3:15 p.m.

9 The moon lies just above Saturn during the early evening hours. The two bright stars above the moon are Castor and Pollux.

12 The Sun enters Pisces on the ecliptic.

13 The moon is at apogee, or furthest distance from Earth, tonight.

14 Full moon, 6:35 p.m. The full moon of March is called variously the Egg Moon, Sap Moon, Crow Moon, or Lenten Moon. There will be a slight, penumbral lunar eclipse tonight for viewers in the northeastern United States and the Maritimes. Look for a faint shadowing on the moon’s right side as it rises in the east at twilight.

20 Vernal or spring equinox, 1:25 p.m. The Sun crosses the celestial equator into the northern hemisphere marking the first day of spring. The Sun enters the astrological sign of Aries but, astronomically, is in Pisces.

22 Moon in last quarter, 2:10 p.m.

25 Look for the crescent moon to the lower right of Venus on the predawn southeastern horizon. Those with strong binoculars may be able to spot Neptune directly bellow Venus.

27 The crescent moon is just to the lower right of Mercury low in the southeast about a half hour before sunrise.

28 The moon is at perigee, or closest approach to the Earth, today.

29 New moon, 5:17 a.m.

31 Sunrise, 5:19 a.m.; sunset, 6:01 p.m.

Clair Wood taught physics and chemistry for more than a decade at Eastern Maine Technical College in Bangor.