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Zodiacal light juts upward to Taurus

The mysterious zodiacal light is often visible after dusk or before dawn from the tropical regions of the world. But at temperate latitudes in either the Northern or Southern Hemisphere, your best chance of catching the zodiacal light in the evening sky is in late winter and early spring – or for the few months centered on the spring equinox.

Since the recent March equinox is the Northern Hemisphere’s spring equinox, right now is the right time for northerners to spot the zodiacal light in the western sky after all traces of evening twilight have disappeared. Look westward, in the direction of sunset, some 80 to 120 minutes after sundown.

Zodiacal light photo by Noriaki Tanaka, taken on March 23, 2014. Look closely and you might see the constellation Orion to the left of center. The tip of the cone brushes against the Pleiades star cluster. The bright object to the upper left is the planet Jupiter, when it was in front of the constellation Gemini. In 2016, Jupiter shines in front of the constellation Leo.

Zodiacal light photo by Noriaki Tanaka, taken on March 23, 2014. Look closely and you might see the constellation Orion to the left of center. The tip of the cone brushes against the Pleiades star cluster. The bright object to the upper left is the planet Jupiter, when it was in front of the constellation Gemini. In 2016, Jupiter shines in front of the constellation Leo.

From the Southern Hemisphere … your best chance to spot the zodiacal light is in the morning sky now. Look for it in the east before sunup if you live at southerly temperate latitudes – or better yet, wait until the moon wanes to a smaller crescent – and finally exits the morning sky – a few days from now. The zodiacal light with a waning crescent moon in its midst can be a lovely sight!

Back to the Northern Hemisphere’s evening view … Taurus is a constellation of the Zodiac, so during a Northern Hemisphere spring, northerners can use Taurus’ two most prominent signposts – the star Aldebaran and the Pleiades star cluster – to help guide you to the zodiacal light in the western sky.

Because the zodiacal light juts upward from the horizon and streams through the constellations of the Zodiac, Taurus serves as your faithful guide to this elusive, glowing pyramid.

Zodiacal light is visible to our eye because it is composed of interplanetary dust particles that reflect the light of the sun. Because these dust particles circle the sun in nearly the same plane that Earth does, the zodiacal light is always seen running astride the ecliptic – Earth’s orbital plane projected onto the constellations of the Zodiac.

So, if you live at northerly latitudes, look for the zodiacal light to point in the direction of Taurus some 80 to 120 minutes after sunset.

Bottom line: For some weeks around the March equinox, the glowing pyramid of light known as the zodiacal light is best seen in the west after sunset from the Northern Hemisphere, and the east before dawn from the Southern Hemisphere.

Bruce McClure

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