Week of September 1-7, 2013

If you haven't checked out Venus glistening low in the western sky at dusk, now would be a great time to do so. Many people might have missed it because of low-lying clouds or mountains blocking the view, but as autumn approaches, it's now beginning to climb higher in our sky as it rounds the sun.

As more and more people spot its brilliant light in the early evening sky, more and more misconceptions about just what it is will begin to pop up. Of course, regular readers of this column won't fall prey to these (you'd better not!), but you may encounter some in your interactions with other, less experienced, stargazers.

Perhaps the most common misconception of novice sky watchers is that the brilliant light of Venus is an approaching aircraft with its landing light on. I suppose this is an easy mistake to make; even a World War II fighter pilot reportedly was fooled and actually fired on the planet.

He missed.

Another common belief is that it's the International Space Station. Of course, ISS orbits the Earth about every 90 minutes, so it appears to drift gracefully across our sky from time to time. Venus doesn't. If you visit the website Heavens Above you can predict the passage of the real ISS across your sky.

Perhaps most puzzling to me is the idea that it's the North Star. I guess it doesn't seem to bother folks that it appears in the west!

Whenever you encounter misconceptions such as these — and I'm sure you will — be patient and take time to explain what people are actually seeing. Helping others enjoy the wonders of the night sky is a tremendously rewarding way of spending your time.

Ever since childhood, I've always enjoyed the company of Venus in the glow of twilight, especially when it's nuzzled up against the delicate crescent moon. Fortunately this sight is not all that uncommon, occurring once a month or so as the moon orbits our planet. And just such a pairing is coming up next weekend.

On Sunday, Sept. 8, the delicate crescent moon will appear not far from brilliant Venus and will form a magnificent sight in the waning light of dusk.

As you admire the pair, be sure to check it out with binoculars, since few celestial sights appear more three-dimensional. You'll surely enjoy seeing the faint disk of the full moon, the result of sunlight reflected off the Earth back onto the dark side of the moon.

The appearance of this ghostly glow was first explained by the famous 15th-century Italian artist and inventor Leonardo da Vinci.

He recognized that when the moon appears as a crescent in our sky, a hypothetical lunar astronomer would see in his sky a nearly full Earth. And, just as a bright moon illuminates the dark night on Earth, a bright Earth would illuminate even more the darkness of the moon. Today we call this phenomenon "Earthshine."

I hope you'll mark your calendars for this weekend's beautiful sky show; I know I'll be out keeping watch at dusk, reliving fond memories that extend way back to my childhood!

Visit Dennis Mammana at www.dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.