If I were going to make an evening hike for a mountain-top sunset and then hike back soon after dark, I’d plan my trip on a night of a waxing half-moon.
A waxing half-moon?
If you are like most of us, you might need a little help here because you studied this stuff in your seventh grade science class, but haven’t had to think about it since that final exam. It’s ironic that we have been able to conquer the darkness with fossil fuels and electricity, but we have become alienated from the things that happen at night – the animals, the stars, and the phases of the moon. We just aren’t outside much after sundown, and when we are, we are usually surrounded by the blinding glare of halogen and neon. So, we’ve lost touch not only with the night sky but with thousands of years of human knowledge. I can’t say that I frequently feel the urge to get in touch with the thousands of generations of humans that have preceded us, but it is nice to know that whenever I look up in the sky and think about the stars or moon, I’m doing exactly that.
Back to our seventh grade science lesson…the moon takes four weeks to go through its entire cycle. It takes one week to go from the tiny sliver of the new moon to a half-moon and another week to go from this “first” half-moon to a full moon. This is its waxing (growing) phase. The third week is spent shrinking (waning) from full to half (the “second” half-moon). The final week sees the moon wane further from half to gone, followed immediately by new again. You probably knew all that.
But here’s the part that is probably a bit fuzzy to you. The various phases of the moon will light up different segments of the night. A full moon will rise in the east at the same time that the sun sets in the west. This full moon will spend the entire night moving across the night sky and will set in the west just as the sun once again rises in the east at the beginning of the following morning. The full moon has enlightened the full night.
You might think that a night hike should take place under a full moon rather than a half moon. Not necessarily. While a full moon will be bright, it will also be low in the sky for the first few hours (and the last few hours) of the night. Depending on when you intend to hike, it may be better to night hike under a three-quarter or half-moon because it will be higher in the sky. Here’s how that works.
The moon rises about an hour later each night as it goes through its month-long cycle. This means that some weeks the moon lights up the first part of the night and other weeks the latter part of the night. A quick and easy way to remember this is to remember that the “early” (waxing) moon lights up the early part of the night, the full moon lights up the full night, and the “late” (waning) moon lights up the late part of the night. So, at the end of the moon’s first week, the moon is half full and is going to light up half the night. Because this half-moon is its first or early half, it lights up the first half of the night – from sunset to midnight. One week later the full moon will light the entire night. Yet another week brings another half-moon – the second or late half-moon. This half-moon will light up the second or late half of the night – from midnight to sunrise.
So, if I will be night hiking in the early part of the night, maybe the first hour or two after sunset, I prefer an early (waxing) half-moon. The fact that it is an “early” moon means that it will light the early part of the night, starting at sunset and disappearing over the western horizon around midnight. The fact that it is half rather than full means that it will be high in the sky when the sun sets.
On the other hand, if I will start hiking at 4 or 5 am, I’ll be hiking at the very end of the night, so I want to hike under the moon in the late weeks of its cycle. I’ll time my hike for a waning half-moon, ensuring that this bright moon will be high in the sky during those couple of hours preceding sunrise.
Or, just write this down in your trail guide: for a pre-dawn hike, it’s best to go 4 to 7 days after the full moon; for a hike soon after sunset, go 4 to 7 days before the full moon. Of course, take a flashlight, just in case.
Good night (hiking).
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