The highlight of my just completed Yosemite Autumn Moon photo workshop was a full moon rising above Half Dome at sunset. But rather than settle for just one Half Dome sunset moonrise, I’d “arranged for” three. Clouds shut us out on sunset-moonrise number two, but sunset-moonrise number one was a huge success. (And sunset-moonrise number three, from Tunnel View, was so special that I’ll dedicate a whole blog post to it.)
Any location’s “official” sun and moon rise/set times assume a flat horizon—if you read that today’s moonrise is at 5:00 p.m., you need to account for the time it takes for the moon to rise above whatever obstacles (mountains, hills, trees) are between you and the flat horizon. And due to the same motion around Earth that causes the moon’s phases, anyone planted in the same location night after night would see the moon rise about fifty minutes later each day (this is an average—the nightly lag varies with many factors). For example, a moon that hovered right on the horizon at sunset last night will rise too late to photograph tonight.
While you can’t do anything about the moon’s absolute position in the sky, you can control the elevation of your horizon simply by changing your location. In other words, careful positioning makes it possible to photograph a moonrise at sunset on multiple nights—move lower and/or closer to the horizon to delay the moon’s appearance, higher and/or farther to view the moon sooner.
The earlier the moon will rise, the closer to your subject (for example, Half Dome) you should be to increase the angle of view; the later the moonrise, the farther back and higher you should be. So, positioning ourselves on the valley floor, close to Half Dome, provided a steep angle of view that delayed the moon’s appearance on Thursday night, when it rose (above a flat horizon) several hours before sunset. Conversely, standing at elevated Tunnel View a couple of nights later decreased our angle of view, enabling us to see the moon sooner when official moonrise is closer to sunset.
Last Saturday night, from Tunnel View on Yosemite Valley’s west side (farthest from Half Dome) the moon was “scheduled” to appear about five minutes after sunset—that would put it in the magenta, post-sunset band with just enough light for about ten minutes of shooting before the dynamic range (the brightness difference between the sunlit moon and darkening foreground) shut us down. While that was the shoot we were most looking forward to, for Friday night I’d picked a mid-valley spot by the Merced River that would put the moon above Half Dome just about sunset. And for our initial sunset on Thursday evening, I took the group to a riverside spot on Yosemite Valley’s east side, much closer to Half Dome.
Clouds obscured the moon Friday night, but Thursday night was a real treat. Not only did we find the fall color in the cottonwood trees upriver still hanging in there (despite a fairly early autumn in most of Yosemite Valley), the clouds parted just in time for the moon’s arrival. In addition to Half Dome, the trees, and the moon in the distance, we were able to get a mirror image of the scene reflected on the glassy surface of the Merced River at our feet.
While the downside of moving closer to Half Dome (or whatever your subject is) is that the wider focal length necessary to include the entire scene also shrinks the moon, I’ve always believed a small moon adds a powerful accent that makes an already beautiful scene even more special. But what if you prefer your moon big? Simple: just wait a day or two, and move back as far as possible. Stay tuned….
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One final point: Notice the cool (blue) color cast of this scene. This is an indication of not just the rapidly advancing twilight, but also the depth of the shade there in the shadow of the steep valley walls and dense evergreens. An image’s color temperature is a creative choice made during processing by photographers capturing in raw (unprocessed) mode. While warming the light would have made the trees more yellow, I decided that the coolness adds a soothing calmness that is lost in the warmth of a daylight scene.