Lori Carey Photography

Tuesday, December 25, 2007

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.