As you no doubt know, the moon orbits Earth, which orbits the sun, and the percentage of the moon we see each night (its phase) changes with the angle connecting Earth, the moon, and the sun. The lunar cycle—the time it takes the moon to circle Earth and repeat a phase (due to Earth’s orbit of the sun, the moon actually has to travel a little more than a full circle to repeat a phase)—is about 29 1/2 days. Because our 12-month calendar cycles in almost the same time, averaging about 30 1/2 days until we return to today’s day next month, we usually have one full moon each month.
But every few years a coincidence of calendar and orbital geometry gives us a phenomenon that probably generates more attention than it deserves. Labeled a “blue moon,” the second full moon in a calendar month is a lot more rare than it is visually interesting, a fact that is lost on the media. Nevertheless, if you want to see the first blue moon since 2012 (the next one won’t happen until 2018), look to the sky Friday night (July 31, 2015), when July’s second full moon will be overhead. Just don’t expect it to look any different than any other full moon.
So what’s the deal with the moon in this image? Captured in the morning gloaming of White Sands National Monument, the blue dunes in this scene were colored by the short wavelengths of indirect sunlight. With the sun still well below the horizon, these blue and violet wavelengths are all the that’s able to survive the trip around Earth’s curve. Rather than white balancing my capture to give the scene a (misleading) daylight quality, I chose to allow the cool light to imbue the scene a more true twilight feel.
If you want to photograph the upcoming full moon at sunset, I suggest you go out Thursday (July 30), when the moon will rise about 45 minutes before sunset—if you wait until Friday evening, when the moon rises almost an hour later, you’ll likely struggle to capture simultaneous detail in the darkening landscape and the daylight-bright moon.
Or you could go out at sunrise tomorrow and Saturday mornings to photograph the moon as it sets in the west after sunrise. Friday’s moonset will be a little closer to sunrise, ideal if you have a fairly good view of the horizon (no high mountains or other obstructions); Saturday’s moon will set later, making it a little easier to photograph (fewer dynamic range challenges).
Learn more about full moon photography in my “Full Moon” photo tips article.
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