Photographers often use reflector boards to control the lighting of their photos by bouncing light from the sun onto other objects. But did you know you can also use your camera to capture reflected light that bounced off the Earth itself? It’s not that difficult, but you do need exactly the right conditions.
Every month just after sunset, it’s possible to see a thin crescent moon in the western sky, chasing the sun through the blue dusk. Occasionally, you see something more: the faint outline of the moon’s unlit portion, almost hidden in the glare of the crescent. What’s happening?
You have to remember that the moon doesn’t create any light of its own. The bright crescent you see is lit up by the sun, and that light is reflected back to earth. That’s why the moon is so much dimmer than the sun—it’s not a very strong mirror. The crescent area of the moon is experiencing “day,” while the unlit portion is still in “night.”
So why can we sometimes see the unlit, nighttime part of the moon? It’s because the Earth receives and reflects sunlight as well. Even though it may be dusk where you’re standing, it’s still daytime off the west where the sun went down. The light from that daytime portion of the Earth bounces back into space and (faintly) lights up the nighttime side of the moon. Then the light reflects again off the moon, coming back to us.
So illumination from the crescent part of the moon has been reflected once, while light from the dim outline has been reflected twice—and has become very faint during the process.
This sight is sometimes called “The Old Moon in the New Moon’s Arms,” or, less poetically, “Earthshine.” You won’t see it every time, but when you do, it’s a lovely and striking sight. Whether or not it’s visible can depend on the width of the crescent moon, along with how cloudy (and thus more reflective) the Earth is on a particular day.
The key to photographing a moon like this is to carefully bracket your photos. Start off with some photos where only the crescent portion is exposed properly (your camera’s spot meter is ideal for this). Then, gradually let more and more light in, until the Earthshine becomes obvious. If you go too far, the crescent moon will overexpose. But eventually, you’ll find just the right exposure that shows a bright crescent, dim Earthshine, and nice blue twilight sky. You might add a tree branch or two into the composition for some added visual interest.
Every month just after sunset, it’s possible to see a thin crescent moon in the western sky, chasing the sun through the blue dusk. Occasionally, you see something more: the faint outline of the moon’s unlit portion, almost hidden in the glare of the crescent. What’s happening?
You have to remember that the moon doesn’t create any light of its own. The bright crescent you see is lit up by the sun, and that light is reflected back to earth. That’s why the moon is so much dimmer than the sun—it’s not a very strong mirror. The crescent area of the moon is experiencing “day,” while the unlit portion is still in “night.”
So why can we sometimes see the unlit, nighttime part of the moon? It’s because the Earth receives and reflects sunlight as well. Even though it may be dusk where you’re standing, it’s still daytime off the west where the sun went down. The light from that daytime portion of the Earth bounces back into space and (faintly) lights up the nighttime side of the moon. Then the light reflects again off the moon, coming back to us.
So illumination from the crescent part of the moon has been reflected once, while light from the dim outline has been reflected twice—and has become very faint during the process.
This sight is sometimes called “The Old Moon in the New Moon’s Arms,” or, less poetically, “Earthshine.” You won’t see it every time, but when you do, it’s a lovely and striking sight. Whether or not it’s visible can depend on the width of the crescent moon, along with how cloudy (and thus more reflective) the Earth is on a particular day.
The key to photographing a moon like this is to carefully bracket your photos. Start off with some photos where only the crescent portion is exposed properly (your camera’s spot meter is ideal for this). Then, gradually let more and more light in, until the Earthshine becomes obvious. If you go too far, the crescent moon will overexpose. But eventually, you’ll find just the right exposure that shows a bright crescent, dim Earthshine, and nice blue twilight sky. You might add a tree branch or two into the composition for some added visual interest.
