Waking Up Early to Watch the Pre-dawn Sky

Clear SkiesBy Scott Levine

We usually spend most of our time around here talking about the comings and goings of things in our nighttime skies. This month, I thought, it’d be fun to skip past the evenings’ prime time and look at the sky in the mornings, just before dawn.

I’ll be the first to admit there isn’t a lot of appeal to getting out of bed early to look at, well, anything. The truth is, a few times a year, I like to make myself an early cup of coffee and slip out into the pre-dawn darkness. There’s a certain calm that comes in the early morning solitude when the neighborhood and the skies belong to us alone. The last couple of weeks of summer are one of my favorite times to do it.

Let’s fast-forward through the night just as the calendar flips to September and look toward the south and southeast at around 5 a.m. There, on the 1st, the first thing we’ll notice is the moon. Do you notice anything unusual about it? It starts the month as a waning crescent, with its lighted left-hand side trailing behind it as it makes its way into morning. In just a few hours, once the stars are washed out by sunlight, we’ll see it arcing above the roofs and trees, etched into the blue and hidden in plain sight.

I always find them a little off-kilter and unsettling because they’re backward from what most of us are used to. It’s just before its “new” phase now. It’ll be back to “normal” in just a few days once the moon slides past the sun and reappears in the evening sky.

Widening our gaze, we’ll see our nearest neighbor is tangled among some familiar faces. These last weeks of summer also give us a sneak preview of Orion, Taurus and the rest of winter’s bright lights. Just above the horizon, we can see our old friend, the brilliant Sirius.

Sirius, which is the brightest star just in our sky (other than the sun), is also the brightest in constellation Canis Major – the greater dog. So, it has the nickname “the Dog Star.” Ancient people believed that the heat from its reappearance in the morning’s skies added onto the sun’s and made the weather hotter than it’s been all through the summer. These last weeks of summer became called the “Dog Days.”

Over the years since, we’ve learned that this simply isn’t true. Sirius is a little over eight light-years away. (A light-year is about six trillion miles.) That’s so far that if you have a third-grader nearby, you can tell them that it’s light left for their eye right around when they were born. That’s very close as these things go, but 48 trillion miles is much too far for its heat to have any effect on our weather.

These stars are here now, but it’ll still be a few weeks before we see this full arrangement in the evenings. We’ll talk more about them then.

There’s something extraordinary about sitting alone and watching the skies before the birds wake up and the delivery trucks make their rounds. I hope you will this month. Clear skies, everyone!

Scott Levine (astroscott@yahoo.com) is an astronomy writer and speaker from Croton-on-Hudson. He is also a member of the Westchester Amateur Astronomers, who are 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 westchesterastronomers.org. Star parties are free and open to the public.


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