Why the full moon isn't the best view of what it has to offer


While a full moon is beautiful, astronomy experts agree it isn't the star of the celestial show.

Why? It's a simple lesson I learned as a child growing up in Brooklyn, N.Y.

I was fascinated by the moon and its many phases. I also learned one of my first lessons about night-sky watching: I couldn't really see the stars well from the middle of a metropolis with all its light and air pollution. By the time I was 10, my family had moved to Greece, and there, in the summer visits to the country, I could see a night sky so removed from urban distraction and so vivid and close I could almost reach out and touch it. Some nights, the moon seemed like an over-sized soccer ball.

As we approach October's full moon this weekend, Jay Pasachoff, Williams College's Field Memorial Professor of Astronomy, said all you really need to do to catch the full moon is to look to the sky.

"I don't know of any special equipment for watching a full moon," Pasachoff said. "Just look in the east as it rises while the sun sets, since the sun at our backs is illuminating it. In fact, the shadows are non-existent for a full moon, while it does brighten because the sunlight bounces back out of any holes it enters."

He insisted, though, the best time to see the moon's surface features was when it was less or more than full.

A crescent moon is less than a half, but more than a new moon, while the gibbous moon is more than half, but less than full. Waxing refers to when the moon is increasing in visible surface, or gaining light, toward a full moon. Waning is when it's decreasing in visible surface and light toward a new moon.

The full moon we will see this weekend even has a name, according to Rebecca Johnson, editor of SkyWatch Magazine and communications director at the McDonald Observatory, University of Texas at Austin.

"This full moon is called the Hunter's Moon," Johnson said. "It's the first full moon after the Harvest Moon, which was last month."

(The Harvest Moon is the full moon that is seen closest to the time of the autumnal equinox).

When the moon is full, Johnson said, it rises shortly before sunset and is directly overhead at midnight. It sets at dawn. While a telescope or binoculars can be used to observe the full moon, just your own eyes is enough, she said.

"A full moon will wash out all but the brightest stars, so it's not the best time for sky watching unless you are focusing on the moon itself," Johnson said. "[But] it is also not the best time to see the moon's features. It's easier to see shadows and dark/light contrasts when the moon is half full."

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There was that truth I discovered back in Brooklyn.

Hugh Crowl, professor of astronomy and physics at Bennington College, told me I was right as a boy, and it was worth explaining why.

"The best advice for seeing interesting things on the moon is to look when the moon is not full," Crowl said. "The full moon is both too bright to really appreciate the details and lacking the nice low-angle light that highlights details on the surface. It's sort of like how photographers on earth find it much more interesting to shoot during morning and evening than high noon."

Crowl said that amateurs didn't need to stop at the moon. This is an interesting time when most of the planets, which are typically some of the most interesting things to look at, are close to the sun in the sky, Crowl explained, so most of the sky is free of planets right now. This opens the way to other viewing.

—Telly Halkias is an award-winning freelance journalist

While the full moon gets all the press this time of year, here are a few more celestial sights worth looking for in the night sky:

• If you are in a relatively dark site, you can see the Milky Way beautifully arcing above your head in the early evening.

• The Summer Triangle, a combination of three bright stars (Vega, Deneb and Altair) is close to directly overhead at sunset, and moves toward the western horizon as the night progresses.

• Near, Vega, the brightest of those three stars that make up the triangle, is the Ring Nebula ("M57"), a faint, diffuse ring of ionized gas that's the remnant of a star, like our sun, that died relatively recently (well, within the last few thousand years). It's visible with a small telescope or, even perhaps with binoculars if you're at a dark site.

• If you're out past 9 p.m. or so, you can see the Pleiades ("M45"), a really beautiful reflection nebula, rising in the eastern part of the sky. It's a beautiful glowing nebula that you can see fairly well with your naked eye, but is also really nice through a pair of binoculars.

• If you're up quite late (after midnight), you'll start to see Orion rising in the east; Orion is a striking constellation in its own right, but it also has a massive star formation region that fills most of the constellation.

— Source: Dr. Hugh Crowl, Bennington College


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