Lunar Eclipse Sequence, 1:23 a.m. to 4:49 a.m., August 28, 2007

Before getting to the topic at hand, I want to thank all of you for your support in launching my new eBook, Light & Land. The first day’s sales were amazing, off the charts, so thanks to all of you who bought a copy. And if you haven’t purchased it yet, there’s still time to get 20 percent off. See my last post for details.

So on to the eclipse… I was honored to have this lunar eclipse photo recently selected for the Natural World Exhibit at the Center for Fine Art Photography in Fort Collins Colorado. By coincidence, there will be another full lunar eclipse Monday Night—an opportunity to try making your own eclipse photograph.

Now here in California there are lots of dire weather forecasts for the next few days, with predictions of five to ten feet of snow above 7000 feet in the Sierra Nevada, and five to ten inches of rain in the foothills and Yosemite Valley. Minor flooding is possible. So there’s a good chance that we won’t see Monday night’s eclipse at all. But you never know—all it takes is a small break in the clouds. And those of you in other parts of the world may have perfect weather for this event. To see where and when the eclipse will be visible (weather permitting), visit the NASA web site.

Moon Position

If the weather cooperates, and you want to try make your own eclipse photographs, here are some tips. First, you should move away from cities to avoid light pollution. Next, the moon will be very high in the sky in the northern hemisphere for this event. The full moon takes the path the sun took six months ago, or will take six months from now. This eclipse coincides with the winter solstice, so the sun will rise east-southeast, take a low path through the southern sky, and set west-southwest. But the moon will behave like the sun in June: rise east-northeast, set west-northwest, and take a high path through the sky. At the peak of the eclipse, 12:17 a.m. Pacific time, in Yosemite the moon will be almost due south at an altitude of 75 degrees—almost overhead.

Now if you want to just photograph the moon by itself, it’s position in the sky doesn’t matter. But if you want to include something in the foreground, that object will have to be tall. Maybe you could look up through a gap in a grove of trees, or in Yosemite Valley position yourself underneath one of the southside rock formations like Half Dome or Cathedral Rocks. Something with a distinctive, interesting silhouette works best. Of course if you live in other parts of the world the eclipse may be lower in the sky, and offer more alternatives for interesting foregrounds.

I made this photograph by taking separate exposures of the moon, each ten minutes apart, and layering them together in Photoshop. The Photoshop techniques are beyond the scope of a post like this, but the short answer is to use the Shift key when dragging one layer on top of another, so they line up exactly, and use the Screen layer blending mode for all but the bottom layer.

To make a sequence you have to predict the path that the moon will take so you can compose your photograph accordingly. The best tool I’ve found for this is an iPhone app called Star Walk. With this program you can look at a section of virtual sky and then spin the Time dial, allowing you to watch a fast-motion movie of the night sky for any time and place. Very cool stuff. If you don’t have an iPhone there are many other applications and online resources that will allow you to determine the position of the moon, just not with such ease. The best of these is probably The Photographer’s Ephemeris, a free desktop application.

Exposure

In the field the hardest part is focusing and getting the right exposure. For tips about focusing, and general suggestions about equipment and techniques for night photograph, see this earlier post about  photographing lunar rainbows.

Light meters are useless for getting good exposures of the moon itself, which is what we’re talking about here, because even with a one-degree spot you can’t meter off just the moon—you’ll be reading both the moon and surrounding black sky. So here are some suggestions based on past experience, including making the accompanying photograph. All the times and f-stops are for 200 ISO, so you’ll have to adapt for other ISOs:

Full moon, or moon more than half visible: 1/60 sec. at f/16

Half to one-quarter of the moon visible: 1/30 sec. at f/16

Less than one-quarter of the moon visible: 1/15 sec. at f/16

Just the edge of the moon lit: 1 sec. at f/16

Fully eclipsed at beginning and end of totality: 4 sec. at f/5.6

Fully eclipsed, deepest totality: 8 sec. at f/5.6

Keep in mind that you don’t want exposures that are too long, as the moon will move and blur. You can get away with 8 or maybe even 16 seconds with a wide-angle lens, but with a telephoto you probably need to keep exposure times to two seconds or less. Consider pushing up the ISO with telephotos. Bracketing exposures is a good idea.

When making the accompanying photograph I used flash to light-paint the trees in between making exposures of the moon. Light painting is a complex subject that I won’t get into here. If this is the first time you’ve ever tried photographing an eclipse I’d suggest you keep it simple, and don’t try light painting. Just try to capture single images of the moon itself, or perhaps a sequence with silhouetted trees in the foreground. Exposures anywhere from 10 to 30 minutes apart can work for a sequence; just make sure to keep the interval the same throughout. Make sure your tripod is solidly planted before beginning the sequence.

When the moon is full, stars are barely visible. But when the moon becomes totally eclipsed an amazing thing happens: the sky gets dark, and thousands of stars appear. In the accompanying photograph I made an exposure for these stars when the moon was fully eclipsed: 30 seconds at f/4 and 3200 ISO. Anything longer than 30 seconds would have turned the stars into streaks. I then cloned the vastly overexposed moon out of this frame, and added this layer to the mix, using the Shift key and Screen blending mode as described above.

You need a lighter frame like these stars to see any silhouettes—otherwise the photograph will just be completely black except for the moon. Another option is to make an exposure when the moon is full and casting some light on the landscape. You’ll have to wait until the moon is well out of the frame, and make sure you shade the lens to prevent flare. Yes, the moon can cause lens flare, and a lens hood is useless for shading wide-angle lenses—use your hand. See that earlier post to find suggested exposures for moonlit landscapes.

Good luck!