Have you ever seen the zodiacal light? This huge pearly pyramid is on its best display in the Northern Hemisphere on moonless evenings from February through April. All you need is a location far from artificial lights (at least 40 miles from a small city and 80 miles from a major metropolis) that also has an unobstructed western horizon.

The pyramid of pearly light reaching from the horizon through the Pleiades (just right of center) is the zodiacal light.

Doug Zubenel

Go out an hour after sunset and look to the west. Even though the Sun is now far below the horizon, a huge dome of light marks the spot where it disappeared. As this light fades and shrinks down to the horizon, another glow will be unmasked; a tall, leftward-slanting pyramid of light. It follows the path of ecliptic, running left of Aries and then between the Hyades and Pleaides, the sky's most spectacular star clusters.

Aside from its shape, you might think it was just part of the twilight, but it will linger long after the rest of the sky is fully dark. The first time I saw the zodiacal light, I thought it was light pollution, but light pollution forms a low band along the horizon. It's amazingly brighter — even brighter than the Milky Way — and once you've seen it, you'll never again have trouble recognizing it.

What are you seeing? The zodiacal light is the combined glow of countless tiny particles (debris from comets and asteroid collisions) that orbit the Sun. See our article Have You Seen the Zodiacal Light? for more information.

Comments


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Melanie

March 5, 2010 at 10:26 am

Can I see the zodiacal light from the city? Or do I need to go to the country, where it's much darker? I've never seen it before, but I really want to.

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Ed

March 5, 2010 at 11:59 am

Mekanie, as stated n the article: "All you need is a location far from artificial lights (at least 40 miles from a small city and 80 miles from a major metropolis)"

Regards,
Ed

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David Fried

March 5, 2010 at 12:14 pm

I just wanted to say that I saw the zodiacal light for the first time last March, just about the time of the equinox, on the beach in Tulum Mexico. It was astonishingly bright, so much so that I was wondering at first what large city lay in that direction, when it was only small and ill-lit Tulum.

I was wondering, though. At 20 degrees N at the equinox, does the ecliptic make a 90 degree angle with the western horizon, so the zodiacal light is oriented vertically?

Thanks.

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Melanie

March 5, 2010 at 5:37 pm

Oh, I didn't catch that. Thanks!

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Gene A, Dees

March 7, 2010 at 12:20 am

Are you saying that you that the Zodiacal light has to be seen in the western sky? Only? Here in New Mexico I have seen it twice in one night ... the classic "after sunset" thing and then I saw it again the same night (early morning?) before the Sun came up. I had never seen it before I moved to New Mexico.

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Gordon Hommes

March 7, 2010 at 5:05 pm

One of the coolest views of the zodiacal light I have had on numerous occasions has been while camped on frozen lakes here in northeastern Minnesota in the Boundary Waters Wilderness. Far from any light pollution, the sky is incredibly dark from horizon to horizon, and during March and April the long pyramid of zodiacal light is vivid and extends across a long segment of the zodiac.

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Robert Sheaffer

March 7, 2010 at 11:57 pm

On Feb. 3 I was camping out a few miles east of Niland, CA, on the east side of the Salton Sea, more than 100 miles east of San Diego. As it was getting dark, I realized that it was getting *very* dark. The winter Milky Way (much fainter than its summer part) was visible all the way across the sky from Cassiopeia through Gemini and Orion down to Canis Major. But looking west, a second band of light was becoming conspicuous, from Pisces up through Aries and into Taurus, ending near the Pleiades: the wide, diffuse band of the Zodiacal light.

This is the best time of the year to see the Zodiacal Light in the evening sky, as its angle with the horizon is nearly vertical. I have only seen the Zodiacal Light conspicuously a few times in my life; that night was one of the best. The
brightest part of the Zodiacal Light was actually *brighter* than the brightest part of the Milky Way, which I had likewise noted years before when I first saw the brilliant Zodiacal Light in the pre-dawn skies of Grand Canyon National Park during the fall.

The light from the Milky Way was in a narrow, irregularly-shaped band. It had a fairly sharp edge, and an irregular shape, getting fatter and thinner in different places. Its color was pure white. By contrast, the shape of the Zodiacal Light was sort of an inverted rounded "V", and it had no distinct edge. It was impossible to say exactly where it ended, it just faded into the background. Most astonishing to me was that its color was clearly seen to be
reddish.

Given how bright the Zodiacal Light can be, I don't know why it isn't seen more often; perhaps we're not "attuned" to perceive a phenomenon of that nature. Oh, and the very clear skies near the Salton Sea are not due to high
elevation, as I'm pretty sure I was below sea level.

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Tony Flanders

March 8, 2010 at 6:08 am

A few clarifications. First, the zodiacal light is technically visible all night every night from any dark location. However, the brightest parts are the parts near the Sun, which are visible in the west after sunset and in the east before sunrise. It's much easier the closer you are to the equator, where the ecliptic always makes a sharper angle to the horizon. In the tropics, it's prominent every clear morning and evening all year round.

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Greg Stone

March 13, 2010 at 1:40 am

Anyone know how long the zodiacal light remains visible?

My best chance right now is on Tuesday, March 16 - from a location overlooking the ocean where I hope I'll have a good shot. But the weather forecast is better for the next day.

Only trouble is, the next day we have a 2-day old moon that doesn't set until about two hours after sunset. So I guess I have two questions.

1. How long after sunset does the zodiacal light remain visible?

2. Assuming it's two hours, or less, will a 2-day-old moon make looking for it hopeless?

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