Shining in the Moon’s Absence

Find a dark spot and take a ride down the river of stars

Thursday’s new moon gives way to a waxing crescent, reappearing low in the west at sunset Saturday. Each following evening, the moon appears 10 degrees higher at sunset and sets more than an hour later.

With the moon out of the picture, the weekend offers a good chance to test your eyes — and the amount of light pollution near your home. Awash in city lights, you’re lucky if you can discern the major constellations and a hundred or two stars at best. Despite our proximity to civilization, however, the Bay’s many dark beaches or a dark rural field are enough to bring the sky to life with thousands of stars.

You know you’ve found a good spot to stargaze when you see the Milky Way on a moonless night. As darkness falls, this river of stars appears as a wide glowing arch dissecting the sky from north to south. While telescopes can pick out individual stars from the many billions, our eyes cannot, and the whole mass instead looks like a diffused, fuzzy light.

Like the planets orbiting the sun, the stars of the Milky Way, our own sun included, revolve around the center of our home galaxy. Moving at more than 150 miles per second, our sun completes one lap every 225 million years.

One of the planets orbiting our sun, Venus, lines up directly between us and the sun on March 27. Called inferior conjunction, this day marks our sister planet’s move from evening skies to pre-dawn skies. You may even be able to see Venus in both the evening and morning skies at week’s end. Over the next week, as the morning star emerges from the sun’s glare, it appears in binoculars or a small telescope as a dramatic, thin crescent, its cusps pointing straight up.