Exploring the Sky During the Long, Carefree Days of Summer
Opinion Advocates for ideas and draws conclusions based on the author/producer’s interpretation of facts and data.
By Scott Levine
The summer solstice – the first day of summer – was about a week ago. This means the first lunar cycle of summer is about to start with today’s new moon (June 28).
There’s an incredible amount we can learn and enjoy by watching the moon’s comings and goings, and this time of year is one of the best times to start.
Here’s a fun project. Fortunately, we’re still close enough to the solstice for this to work, so let’s get to it.
We think of the summer solstice as the day that has the most daylight of the year, but there’s always the same amount of time in a day, a full rotation of Earth. No matter what time of year it is, it’s always about 24 hours. For the summer solstice to have the most daylight, the sun needs to be above the horizon longer than, say, in December, near the shortest day.
To account for these changes from longest to shortest, we see the sun take longer and shorter paths across the sky.
The solstice also marks the highest – and longest – path across the sky that we see the sun take. At noon (or actually 1 p.m., thanks to daylight savings time), when the sun is due south and at its highest point, we’ll see it almost at the very top of the dome.
Since the days are at their longest, the nights must be at their shortest. This means the moon has less time to make it across the sky during its nighttime phases. The full moons of June and July, near the summer solstice, are when its path is its shortest for the year.
As July starts, let’s head out to find the moon. Anytime is fine, but my vote is to start around July 4. That’s when the moon is just before first quarter and starts to be up late enough to see deep into the evening. As we move toward the full moon on July 13, notice how close to the horizon it is when it reaches due south.
Then, as day comes, find the noontime sun and see how high it crosses the sky.
If you need any more proof that summer is fleeting, here it is – the solstice isn’t just the start of summer, but it’s also the end of the part of the year when the days get longer. From that moment on, there’s less and less daylight, almost imperceptibly at first, but then it accelerates as we move through July and into August. Every cannonball we do at the pool, every s’more we eat while camping leaves us with a little less daylight than the day before.
Little by little as the weeks and months go on and the days begin to shorten, we’ll see that gap between the sun and moon close. By September and the start of fall, they’ll be almost exactly the same. Come December, they’ll have switched; the moon will cross high overhead, while the sun mopes across the southern horizon.
It’s easy to say nothing happens in the sky, but there’s magic every day and night of the year, and we get to watch it happen together.
I hope you’ll look up 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.
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