Lori Carey Photography

Monday, December 24, 2007

Full Moon

Last night's December full moon is known as the Full Cold Moon or the Full Moon in Cancer. The moon had a halo when it first rose, and as an added bonus, Mars was near opposition and so was just to the lower right of the moon.

Although I am by no means an expert, or even very good, at astrophotography, I have photographed the moon enough times to realize that the vast dark night sky tricks the camera meter into wanting to overexpose the moon, and so I bracket different exposures that my camera protests will yield a vastly underexposed image. I usually use f/8 or f/11, and I have the most success with

a shutter speed of 1/50.

The problem I had last night is that properly exposing for the moon wouldn't capture the halo, and capturing the halo meant overexposing the moon. With several bracketed shots I had hoped to be able to combine two exposures, but for some reason last night I just couldn't combine two in a way that looked natural for me. So the image you see here is a result of using layer masking on an image that was exposed for the halo at f/8 and 1/50. This image retained sufficient data in most of the overexposed portions of the moon (that's one of the benefits of shooting RAW), and I was able to bring it back with a levels and a curve adjustment to just the moon. It's far from being perfect, and I'm still not happy with the way the halo looks, but every good image of a moon halo that I've found so far on the astronomy sites show the moon itself completely blown out. I'll have to play around with exposures a bit more the next time I see a moon with a halo.

Here is another image with the aperature stopped down to f/11 and the shutter at 1/50 so you can see the difference that just one stop makes in the final image.

I like this exposure of the moon much better, but absolutely no light from the halo was captured.

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