Shoot the Moon: Advice and Apps for Celestial Photography

The Ponzo illusion, in which two identical lines appear different lengths when placed against a background that simulates depth

I’ve had the assignment to shoot the moon several times in my career. The last time was for the opening title sequence for an HBO project. I’ve found that it can be a challenge to photograph the Earth’s only natural satellite.

The first thing to understand is that the way we see the moon, especially when it is close to the horizon, is an optical illusion. The moon is not actually larger in the sky when it’s near the horizon, though it appears that way. It’s not a trick of the atmosphere—it’s just the way our brain interprets what we are seeing.

This effect is akin to the Ponzo illusion, in which two identically sized parallel lines appear to be two different sizes when they’re placed over converging lines. This happens because our brain interprets the converging lines as parallel lines going off into the distance, like railroad tracks. When we see the horizontal lines laid across the converging ones, our brain sees the horizontal closest to the convergence point as larger because it is assumed to be further in the distance.

Your camera does not suffer this same optical illusion, however. Most people who try to photograph the moon are horribly disappointed when it appears as a small speck in their photo, as opposed to the gargantuan glowing orb they see in the sky.

Jay Holben prepares to shoot a moonrise as the sun sets using a Canon EOS 7D and a 600mm lens.

Photographing the moon in all its glory requires a long lens—the longer the better. In my last project I used a Canon L 600mm f/4 lens on my EOS 7D, which gave me the apparent field of view of a 960mm lens—that got me plenty close to my bright subject.

Setting proper exposure for the moon is often a surprising experience. You’re more or less photographing a light source. The moon is just one big reflector in the sky bouncing back sunlight, so it takes a shorter exposure than one might imagine. I set my ISO at 320 and my aperture between an f/8 and f/11. This exposure keeps good detail and texture in the moon’s surface.

In addition to using a good telephoto lens and a deep exposure, there are some great iPod/iPhone/iPad apps that can help you plan your moonshine run. Moonrise and set times can vary by as much as an hour each day. Just because it’s time for a full moon doesn’t mean that the full moon will actually be up in the sky at night—it could be up during the day! Planning ahead will save you frustration and unnecessary effort.

PhotoMoon

At the top of my list is PhotoMoon from Rivolu (iPhone and iPad, $2.99). The app’s main interface is a moon summary page that provides a visual depiction of the current moon phase, as well as moonrise/set times and sunrise/set times for the current date, and the most recent dates for the major phases of the moon.

The app includes a calendar that shows the moon’s phase for every day of the month. Alternately, select a moon phase and it’ll tell you when to find it that month. PhotoMoon also offers a linear graph showing the moon’s visibility in your GPS area compared to the sun’s visibility (there’s often a lot of overlap). You can slide a marker along this screen to see the moon’s compass position and declination at any given moment during that date.

Clinometer

The most powerful screen—a dual view of a compass and an elevation graph—is accessed from the main screen with a side swipe. At the bottom of the screen is a slider that lets you select a time between moonrise and set; once selected, a tiny graphic of the moon appears at the proper compass and elevation positions on the graphs, along with text detail. Using this tool you can plot the position of the moon and know where it will be before it gets there. Will it be obscured by trees, mountains or buildings, or will you have a clear shot? This tool will tell you. I wish this app included an active compass and inclinometer.

SkyView

For that, I reach for Clinometer, a level and slope measurement app from Peter Breitling (iPhone, $0.99). Using the incline measurement tool in Clinometer, sight along the side of your iPhone and the app will give you the precise degree of that elevation. I haven’t yet found a standalone compass app that’s better than my actual Silva Type 15 Ranger compass, so I just use that.

Another great application is SkyView from Terminal Eleven (iPhone, free/$1.99), which I find to be simpler but slightly less accurate. It’s still an excellent resource, though. SkyView uses your phone’s GPS and camera to superimpose constellations, satellites, planets and other space stuff over your iPhone camera’s picture preview. Want to know what the bright star is above your house? SkyView will tell you!

SkyView can also show you the path of large celestial bodies (including the moon) over the course of the day. It’s a great way to very quickly see where the moon will be at a given hour without a compass or clinometer. Just point your phone’s camera at the moon’s current location (if it’s daytime, the moon could be below the horizon), touch the moon icon on the screen and the app will tell you what you need to know. It’s not as accurate as PhotoMoon, but it’s great for quick information and previsualizing your shot.