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A Moment of Balance

Equinox divides not only day and night but the seasons, too

The new moon winks from sight Friday, obscuring the sun in a total eclipse as seen in a narrow strip over northern oceans. Only residents of a few scattered islands between northern Great Britain and Greenland will see the full eclipse, but viewers across Europe and parts of Asia and Africa will see a partial eclipse.
    The nascent crescent moon returns just after sunset Saturday low against the western horizon. Look just above the crescent’s right tip for Mars, so faint you might need binoculars to see it. In contrast, Venus blazes a dozen degrees above the moon and puny Mars.
    The moon is much easier to spot Sunday evening, now to the left of Venus. About a fist-width to the upper right of the Evening Star, look for the second-magnitude star Hamal, the brightest in the minimalist constellation Aries.
    Monday, the waxing crescent moon shines well above Venus and below the Pleiades star cluster. Venus is so bright you can see it before the sun sets, but you’ll need full darkness to see the stars of the Pleiades, which make up the shoulder of the constellation Taurus. With the unaided eye, most people can see only six of the Pleiades, also known as the Seven Sisters. With binoculars, however, there are far more stars than sisters. The Pleiades is an interstellar incubator of gas and dust with thousands of stars dating back 100 million years. A mere 430 light-years from earth, the Pleiades is one of the nearest star clusters.
    Tuesday, the moon passes close to Aldebaran, the red eye of Taurus the bull, and the constellation’s other star cluster, the V-shaped Hyades. In Greek myth, these were nine sisters, daughters to Atlas and half-sisters to the Pleiades, which are off to the right. The Hyades mark the face of the bull.
    Friday’s vernal equinox ushers in spring for us in the Northern Hemisphere. At 6:45pm EDT, the sun hovers directly above the equator. High above the equator extending into space is another equally imaginary line, the celestial equator, which divides the heavens into a northern and a southern hemisphere. For the past six months, the sun has been in the southern celestial hemisphere, robbing us of more daylight the farther south it dips.
    Since winter solstice the sun has inched away from its southern nadir, and our days have grown longer. On the vernal equinox, the day is divided more or less equally between light and darkness.
    For the next three months, the sun climbs higher and higher into the northern celestial hemisphere before reaching its northern apex above the Tropic of Cancer on the day of summer solstice. Then it spends another three months slowly dipping southward to the second point of balance, the autumnal equinox.