The Summer Skies Can Be Exciting With a Little Patience and Luck
Opinion Advocates for ideas and draws conclusions based on the author/producer’s interpretation of facts and data.
By Scott Levine
I know what you’re going to say. “It’s summer. The skies are no good for watching the stars.”
It’s true, just after the summer solstice, which is the shortest night of the year, true nighttime darkness doesn’t come until deep into the evening. That, and the humidity and mosquito-laden haze that settles over us, are enough to make us wait for another night.
Mosquitoes or not, the early summer skies are full of great reasons to look. In fact, let’s look at that slow-coming darkness.
Where we are, the sun sets on June 27 (the night this article is published) at about 8:32 p.m. That’s the latest sunsets get around here. If we lived farther north, or farther west within our time zone, there would be a later sunset. As we’ve all noticed, though, the sky doesn’t go dark the instant the sun drops below the horizon. Instead, our atmosphere is thick enough to scatter the sun’s light so we can still see remnants of our day lingering for a while afterward. The moon, which has no substantial atmosphere, drops into darkness when the sun sets.
After sundown, we gradually move through three phases of twilight. First comes civil twilight. This is the part of the evening after sundown when it’s still bright enough to get around without headlights or other artificial lighting. The only things we can see in the sky are the brightest of the bright.
Let’s look toward the west and see if we can spot Venus. It’s been with us for months and is still utterly eye-catching. In fact, I feel like it somehow seems brighter against the dusk than it does later in the evening. Tonight’s moon is around first quarter, toward the southwest. Its right-hand half is lit, as it follows the sun toward the horizon.
A bit later, we enter nautical twilight. It’s dark enough for sailors to navigate by the few stars that have started to poke through. Maybe we can spot Spica, in Virgo, near the moon. Reddish Arcturus is about halfway up toward the top of the sky. Toward the north, the Big Dipper, and eventually Polaris – the North Star – join the night.
Soon, we’ll come to astronomical twilight, when it’s dark enough for astronomers to start getting their work done. Now, more and more stars appear. Soon, we’ll easily find Vega, which we’ll talk about again later this summer. It’s toward the northeast. Can we find Corona Borealis (the northern crown), the C-shaped clutch of stars very high toward due south? Its brightest star is Alphecca.
It’s not until after 10:40 p.m. – two hours after sunset – that the sun falls far enough below the horizon, and enough darkness has come, for night to begin. With good, dark skies, we’d feel like we’re almost swimming in a deep pool filled with stars.
This time of year, night is short. By around 3 a.m. we’ll start to see the first glimmers of tomorrow’s dawn as we enter morning’s astronomical twilight. Then the cycle reverses, and we move toward day.
I agree, the skies this time of year can be tough, but all you need is a little time, patience and clear skies. I hope you’ll look up this month.
Scott Levine (astroscott@yahoo.com) is an astronomy writer and speaker from Croton-on-Hudson. He is also a member of Westchester Amateur Astronomers, a group dedicated to astronomy outreach in our area. For information about the club including membership, newsletters, upcoming meetings and lectures at Pace University and star parties at Ward Pound Ridge Reservation, visit www.westchesterastronomers.org.
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