We all know of Earth Day, but what about Dark Sky Week?     “I want people to be able to see the wonder of the night sky without the effects of light pollution,” says Jennifer Barlow, who came up with the idea of Dark Sky Week as a high school student in 2003. “The universe is our view into our past and our vision into the future … I want to help preserve its wonder.”

As the sun sets, Jupiter shines high in the southwest, smack-dab in the middle of the constellation Gemini, its bright stars Castor and Pollux a few degrees away toward the celestial zenith. By midnight the king of the planets hovers above the horizon and sets within another hour.

As the sun sets, Jupiter shines high in the southwest, smack-dab in the middle of the constellation Gemini, its bright stars Castor and Pollux a few degrees away toward the celestial zenith. By midnight the king of the planets hovers above the horizon and sets within another hour.

The moon waxes through the weekend, until Tuesday’s full moon, known as the Grass Moon, the Egg Moon and the Pink Moon. This is also the first full moon since vernal equinox, the Paschal Moon, marking the start of Passover and setting the date for Easter the following Sunday.

As the sun sets Thursday evening the waxing crescent moon appears high in the south, its lower tip pointing to the star Aldebaran a few degrees away. Aldebaran is a red-giant that marks the eye of Taurus the bull. Just to the left of the moon is the Hyades cluster, a V-shaped pattern of stars that make up the face of the bull. Higher above the moon is the Pleiades cluster, marking the bull’s shoulder. Named after the seven daughters of Atlas, six of the mythological sisters are visible to the naked eye. How many can you spot?

The waning crescent moon ends the week low in the southeast before dawn. Sunday marks the new moon, the second in March. But it’s not gone long, reappearing as a thin sliver above the western horizon at sunset on the 31st.     With the moon out of sight much of the night, this week provides one of the best chances to see the zodiacal light, a hazy glow that extends like a cone from the western horizon pointing heavenward also called false dawn. It appears an hour or two after sunset, and you’ll only see it with clear, dark skies.

Perhaps you’ll be at lunch Thursday at 12:57pm. Or maybe you’ll be busy at work or school. At that particular time, however, the sun shines directly above the equator. That morning it rises due east, and that evening it sets directly west. This is the vernal equinox, the first day of spring for the 90 percent of the world’s population living in the Northern Hemisphere. In the Southern Hemisphere, it is the first day of fall. Regardless of where you live, your day will be more or less split equally between daylight and night.

With our return to Daylight Saving Time, I wake greeted by Venus blazing in the southeast. The Morning Star rises around 5:30, and an hour later it is well perched above the horizon, shining brighter than any object other than the moon and sun. As sunrise nears and if the sky is clear, another bright light appears 20 degrees in Venus’s wake, Mercury.

Despite our recent snowy, cold spell, signs of spring are everywhere as the earth awakens from its winter hibernation. Long ago, the Celts of pre-Christian western Europe called this time of year the quickening. To them, all objects of Earth — not just creatures, but trees, stones and the ground itself — were alive, all sharing the same sap of life. Now, deep within the still-bare trees, the sap of life flows, birds build new nests; shoots of the earliest spring flowers pierce the frozen soil. All around us, the earth’s pulse is picking up its pace.

The Globe at Night campaign continues through the end of the month, so you still have a chance to contribute to this stellar effort. “Citizen scientists” — that’s you and me — are asked to study the constellation Orion and upload your sightings to the organization’s web site. Find details at www.globeatnight.org.