Posted on January 7, 2018
So just what is so “super” about a “supermoon?” Maybe another way of asking the question would be, if I hadn’t told you that the moon in this image is in fact a supermoon, would you be able to tell? I didn’t think so. So what’s the big deal? And why do we see so many huge moon images every time there’s a supermoon? So many questions….
To understand what a supermoon is, you first have to understand that all orbiting celestial bodies travel in an ellipse, not a circle. That’s because, for two (or more) objects to have the gravitational relationship an orbit requires, each must have mass. And if they have mass, each has a gravitational influence on the other. Without getting too deep into the gravitational weeds, let’s just say that the mutual influence the earth and moon have on each other causes the moon’s orbit to deviate ever so slightly from the circle it seems to be without precise measurement: an ellipse. And because an ellipse isn’t perfectly round, as it orbits earth, the moon’s distance from us depends its position in its orbit.
An orbiting object’s closest approach to the center of its ellipse (and the object it orbits) is at “perigee”; its greatest distance from the ellipse’s center is “apogee.” And the time it takes an object to complete one revolution of its orbit is its “period.” For example, earth’s period is one year (well, 365.25-ish days), while the moon’s period is a little more than 27 days.
But if the moon reaches perigee every 27 days, why don’t we have a supermoon every month? That’s because we’ve also added full moon to the supermoon’s definition—since the sun/moon/earth alignment causes the moon’s phases, and the earth rotates the sun, lunar phases are on a 29.5-day cycle (29.5-ish days from full moon to full moon). So each full moon occurs at a different distance from earth than the previous full moon.
While perigee, apogee, and period are precise terms that can be measured to the microsecond, a supermoon is a non-scientific, media-fueled phenomenon loosely defined a moon that happens to be at or near perigee when it’s full. To you, the viewer, a full moon at perigee (the largest possible supermoon) will appear about 14% larger and 30% brighter than a full moon at the average distance. The rather arbitrary consensus definition of the distance that qualifies a moon as a supermoon is a full moon that is within 90 percent of its closest approach to earth.
I really doubt that the average viewer could look up at even the largest possible supermoon and be certain that it’s different from an average moon. And all those mega-moon photos that confuse people into expecting a spectacular sight when there’s a supermoon? They’re either composites—a picture of a large moon inserted into a different scene—or long telephoto images. I don’t do composites, but they’re a creative choice that I’m fine with others doing as long as they’re clearly identified as composites.
For an image that’s not a composite, the moon’s size in the frame is almost entirely a function of the focal length used. I have no idea whether most of the moons the full moon gallery below were super, average, or small. The images in this and my previous blog post were indeed super, taken within minutes of each other last Sunday evening, at completely different focal lengths.
I used to resist using the supermoon label because it’s more of a media event than an astronomical event, and it creates unrealistic expectations. But since the phenomenon appears to be with us to stay, I’ve changed my approach and decided to take advantage of the opportunity to:
A full moon gallery (super and otherwise)
Click an image for a closer look and slide show. Refresh the window to reorder the display.
Posted on January 4, 2018
A man with a plan
It was New Year’s Eve and I was perched on a cliff overlooking Yosemite Valley, two feet from certain death and ten minutes from the rise of the largest full moon of 2018. While the death thing would have only been a problem if I’d have lost my mind, the moon’s appearance was entirely subject to the whims of Nature. And at that moment, she wasn’t cooperating.
The vast majority of my images are the result of a plan. But planning in nature requires both flexibility and resolve—an ability to adjust and persevere rather than quit when things don’t unfold as expected.
The master plan for this trip was to photograph 2018’s largest moon twice, on opposite sides of the Sierra. I’d start with super-telephoto shots of the moon’s appearance above Yosemite Valley at sunset on December 31, then drive to Lone Pine (just 100 or so miles as the drone flies, but more than 350 miles as the car drives) to capture its disappearance behind Mt. Whitney at sunrise on January 2. Unfortunately, it seemed that each day leading up to my trip, the weather forecast for both locations trended worse. But moon or not, can you think of a better way to celebrate the New Year than circumnavigating the Sierra? Me neither.
Assembling the parts
A beautiful scene is one part landscape and one part conditions (light, weather, and so on). We generally know where the great landscapes are, but finding them in the right conditions requires research, planning, and execution (plus a little luck). I try to time my trips, workshops and personal, to coincide with these special moments, usually some weather or celestial event. Whether it’s lightning at the Grand Canyon, the Milky Way above Kilauea or the bristlecone pines, or a moon rising or setting behind Half Dome or Mt. Whitney, I want to be there.
The problem is, nothing in nature is guaranteed. We know to the microsecond where the sun, moon, and stars will be at any given time, but have no way of knowing what weather we’ll encounter. I’ve lost many a shoot to inconveniently placed clouds, and I’ll never forget the time I scheduled an entire Yosemite workshop based on the anticipated arrival of Comet ISON, only to have the comet go all Icarus on me just days before the workshop.
But experience has taught me that regardless of the score you don’t leave the game until the last out, and you don’t cancel just because the odds are against you. Sometime the odds are wrong, and sometimes I end up getting an unexpected gift that feels like a reward for my persistence. One of the most memorable shoots of my life happened on a morning with clear skies forecast, but we ignored the forecast and went out for sunrise anyway. And I ended up getting the last laugh on the ISON workshop when Yosemite Valley became the beneficiary of a snowstorm and sudden cold that coated every exposed surface in sparkling ice crystals.
Meanwhile, back on the ledge…
It turns out that my Sierra circumnavigation didn’t yield the big moon images I’d planned, but it definitely delivered in many ways. Ignoring the clouds, I arrived in Yosemite Valley on New Year’s Eve afternoon and ended up at my chosen location at around 4:00 p.m. The sky was mostly clouds, but a few patches of blue in the east gave me reason to hope.
The spot I’d chosen was indeed on a cliff 300 vertical feet above Yosemite Valley, but it was only dangerous if I wasn’t paying attention to what I was doing, and given my relationship with heights, there was little chance of that. Flanked by two tripods, I kept one eye on the horizon and the other on void at my feet. On my big tripod (RRS TVC-24LS) was my Sony a7RIII and 100-400 GM with a 2x teleconverter; on my compact tripod (RRS TQC-14) was my Sony a7RII and 70-200 f/4. Each tripod had one leg about two inches from the edge and two legs in the shrubs at my back. Me? I had two legs firmly planted on the narrow granite shelf, with my backside hugging the shrubs.
Sunset was at 4:50. With a cloudless sky the moon would appear from behind Cloud’s Rest at around 4:30, a location similar to last month’s full moon but closer to El Capitan. I’d hoped to start the moonrise with a long telephoto, then transition wider as it rose, but by 4:20 the persistent clouds made it pretty likely that if I saw the moon at all, it would be well above Cloud’s Rest and too high for a telephoto shot. At around 4:30 I waved a white flag at the big moon idea and replaced the 100-400 lens with my Sony/Zeiss 24-70 f/4, hopeful that the moon would make its way into a gap in the clouds before the sky became too dark. At around 4:45 the moon teased with a brief appearance between the clouds, but they scissored shut before the moon had an opportunity to shine.
While waiting I worked on my revised composition, which was complicated by my desire to include with the distant moon and Yosemite Valley, a dead tree in my immediate foreground. With very little margin for depth of field error, I opened my hyperfocal app and plugged in the numbers to determine the f-stop and focus point that would ensure front-to-back sharpness. With that out of the way, I bided my time photographing beautiful warm light on El Capitan and Half Dome.
The moon finally peeked above the clouds for good at 4:48. Ascending the darkening sky, the moon was enhanced by a sheer film of nearly transparent clouds that started out pink that intensified to fuchsia on their way to a vivid magenta that colored all of Yosemite Valley. I kept clicking as the foreground darkened, magnifying my image periodically to be sure I wasn’t losing detail in the moon. The image I share here was captured fifteen minutes after sunset.
You win some and you lose some
The Lone Pine segment of my trip was a photographic flop, but photography really shouldn’t be all about the photography. I arrived in Lone Pine mid-afternoon on New Year’s Day and spent the remaining daylight doing reconnaissance for the next day’s sunrise moonset. This was going to be another super-telephoto opportunity, this time at a location I’d driven past but never photographed from, so I wanted to ensure no surprises. That afternoon I enjoyed nice clouds and light above the Sierra’s east face, but to have photographed it would have compromised my scouting objective so I was just content to enjoy.
I rose before 6:00 a.m. on January 2 and drove out to my planned location with a pretty good idea that the clouds would shut me down. When I parked, the moon penetrated the clouds as an indistinct glowing sphere. As I waited, it descended into more-dense clouds and disappeared for good, but I stayed, quite content to simply watch Mt. Whitney and its towering neighbors emerge beneath the brightening sky.
The drive home took my beneath the serrated Sierra crest, past Mono Lake, through the Hope Valley, over Echo Summit and back down into Sacramento, completing the circuit with at least one successful image and many memories of a great trip. A very Happy New Year indeed.
Click an image for a closer look and slide show. Refresh the window to reorder the display.
Posted on December 19, 2017
This month’s Yosemite Winter Moon photo workshop group got the rare opportunity to photograph a full (or nearly full) moon rising above Half Dome at sunset on three consecutive nights. One reason it’s rare is that, as viewed from Yosemite Valley, the full moon and Half Dome only align in winter. But the real tricky part is making it happen three times when sunset happens at pretty much the same time each evening, but the moon rises about 45 minutes later.
My goal for photographing a rising full moon is to get the moon on the horizon in the window from 15 minutes before to 15 minutes after the “official” (flat horizon) sunset. Earlier and there’s not enough contrast and the moon looks bland; later and there’s too much dynamic range to capture detail in the dark landscape and daylight-bright moon.
The key to making this work starts with understanding that when you see a sunset or moonrise time published for a location, that time is always based on a flat horizon. So unless you’re atop a mountain or on a ship at sea, you’ll probably see the sun disappear behind the terrain in the west before sunset, and you’ll probably need to wait for the moon to rise above the terrain in the east.
Since the sun is at my back when a full moon rises, I’m not too concerned about the precise timing of the sun’s disappearance. But I need to be pretty dead-on for the moon’s arrival. Knowing the moon will rise an 40-60 minutes (or so) later each day, it’s easy to infer that the more days until the full moon, the higher the moon will be at sunset. Sadly, I have no control over the timing of the absolute sunset/moonrise, but I can control the elevation of the horizon, and therefore the moon’s appearance on a given day, by choosing my position relative to the horizon above which the moon will rise.
To make this workshop’s consecutive moonrises work, each evening I picked a view that was farther from Half Dome than the previous evening. On our first evening I chose a spot on the east side of Yosemite Valley; the next evening we were closer to the middle of the valley; on our the third evening our vantage point was near Tunnel View, at the opposite side of Yosemite Valley from Half Dome. The moon rose later above the flat horizon each evening, but by moving farther away, we reduced the distance the moon had to travel before it appeared.
Big moon, small moon
The other thing this little exercise illustrates is how to make the moon big in your frame. Notice that in each image, Half Dome is more or less the same size, but the moon gets progressively bigger. That’s because on any given day, no matter where I am on Earth, the moon is so far away that its apparent size doesn’t change. But the size of earthbound features, like Half Dome, changes a lot with proximity. When I was on Yosemite Valley’s east side for the first moonrise, filling my frame with Half Dome required just a little more than 100mm; the next night I was far enough back to require about 250mm to fill the frame; and on the final night, from eight miles away I needed more than 500mm. And as my focal length increased, so did the moon’s size in my frame.
Posted on January 7, 2017
Are you insane?
Albert Einstein defined insanity as doing the same thing over and over again and expecting different results. Hmmm. For some reason this makes me think of the thousands of aspiring landscape photographers with portfolios brimming with beautiful images that they can’t sell.
Despite a great eye for composition, all the latest gear, insider knowledge of the best locations, and virtual guru status with Photoshop, somehow they haven’t managed to separate themselves from the large pack of other really good photographers. Their solution to anonymity is more: more locations, more equipment, more software. (Perhaps you even know such a photographer.) Compounding the problem, many photographers have become so mesmerized by technology that they turn over control of the most important aspects of their craft to their camera, completely discounting the most powerful tool at their disposal, the one on top of their shoulders.
Knowledge vs. understanding
Just as a new camera won’t make you a better photographer, neither will simply upgrading your knowledge of the latest gear, or accumulating . Knowledge is nothing more than information ingested and regurgitated. On the other hand, understanding is fundamental insight into the workings of a process. While knowledge might enable you to impress table-mates at a dinner party, understanding gives you the ability to use information to create new knowledge—solve problems.
Many photographers invest far too much energy accumulating knowledge, and far too little energy understanding what they just learned. For example, I see many photographers relying on a formula for determining the shutter speed that freezes star motion at a given focal length, oblivious to the fact that this formula doesn’t consider other equally important variables such as display size and the direction the camera is pointing (yes, that’s important). Similarly, simply knowing that a longer shutter speed, bigger aperture, or higher ISO means more light is of limited value if that knowledge doesn’t translate into an understanding of how to manage light, motion, and depth with your camera.
Pretty much anyone can pick up a camera, put it in auto exposure mode, and compose a nice image. While the automatic modes in most cameras “properly” (conventionally) expose most scenes, they struggle in the limited light, extreme dynamic range, and harsh conditions that artistic nature photographers seek. Worse than that, relying on the automatic exposure modes eliminates a photographer’s best opportunity for creativity—the ability to control a an image’s depth, motion, and light.
Too many aspiring photographers are stuck creatively because their unwavering faith in technology leaves them with a critical deficiency in two fundamental, related photographic principles:
Books and internet resources are a great place to start acquiring these principles, but the knowledge you gain there won’t turn to understanding until you get out with your camera and apply them. When these principles become second nature, you’ll be amazed at what you’ll be able to accomplish with your photography.
Insanity is in the mind of the beholder
If landscape photography already gives you everything you want, by all means continue doing what you’re doing. But if you’re having a hard time achieving a creative goal, I suggest that the solution is likely not doing more of what you’re already doing. Instead, start by reevaluating your comprehension of fundamental photographic principles that you might not have thought about for years. You’ll know you’re there when you have complete control of the light, motion, and depth for every scene you encounter, know how to get the result you want, or understand why it’s simply not possible.
Do I really think you’re insane for doing otherwise? Of course not. But I do think you’ll feel a little more sane if you learn to take more control of your camera.
About this image
The image at the top of the post is from a visit to Yosemite this past December. I’d guided my workshop group here for the rise of a nearly full moon, crossing my fingers that clouds wouldn’t obscure our view. The clouds exited just in the nick of time for us to enjoy a beautiful moonrise into the indigo twilight. I started with fairly tight compositions when the moon was close to Half Dome, but in the still, chilled air shortly after sunset, a thin radiation fog formed above Leidig Meadow and I started looking for a wider composition that would add the meadow to the moon and Half Dome.
Before thinking about the scene’s light, depth, and motion variables, I spent a lot of time just assembling the elements of my composition. I decided to frame the scene with Half Dome on the left and Sentinel Fall on the right, positioning myself so a group of tall foreground evergreens, mirrored by towering Sentinel Rock in the background, anchored the center of my frame. I knew that would require a wide composition that would render the moon very small, but I moved back as far as I could to allow the longest possible focal length to avoid shrinking the moon to pinhole size.
By far my biggest exposure concern was dynamic range—the moon is daylight bright, while the rest of my scene was deeply shaded. Normally I trust my histogram in these high dynamic range situations, but in this case the moon was so small that I knew it wouldn’t register. Instead I used my Sony a7RII’s pre-capture “zebra” highlight alert that indicates the parts of my scene that are overexposed.
At just a little wider than 24mm, with no significant detail in my immediate foreground, I stopped down to a fairly diffraction safe f/9. I’m always at ISO 100 unless I can’t achieve the amount of light I want at my ideal aperture and shutter speed, and in this case ISO 100 worked just fine. With my f-stop and ISO set, I increased my shutter speed slowly, checking the moon after each 1/3-stop click for the zebras (if you don’t shoot mirrorless, you can set blinking highlights and check the moon for “blinkies” when you review the image on your LCD). Since I know my camera well enough to know that I could push my exposure at least a full stop beyond the point where the zebras appeared, then recover the highlights in the Lightroom raw processor.
This image looked quite dark on my LCD, and the histogram was way to the left, but after loading it onto my computer and pulling the Lightroom Shadows slider to the right, I recovered an unbelievable amount of clean (low noise) detail, even in the darkest shadows. I just continue to be blown away by the dynamic range of this a7R Mark 2 sensor that enables me to capture scenes I’d never imagined possible in my previous (Canon) life. In this case I probably could have brightened the image further in processing, but I wanted a more moody, twilight feel.
Posted on November 14, 2016
The media tends to distort facts and blow events out of proportion. Perhaps you’ve noticed. The latest example is this week’s “supermoon,” an event heralded on TV, in print, and online like the Second Coming. Okay, now for a little perspective. Despite hype to the contrary, a supermoon occurs at least twice, and up to five times, in a year. In fact, our last supermoon was all the way back in October, and the next one isn’t until December.
But, as I’m sure you’ve heard, this month’s supermoon was special, an event the likes of which we haven’t seen since 1946, and won’t see again until 2034. True enough. But exactly how special was it? Not nearly as special as you might have heard: the diameter of the “epic” November supermoon was only one-half of one percent (.57) larger than the October full moon, and four-fifths of one percent (.84) larger than the December full moon—differences that are impossible to discern with the naked eye. Next year we’ll get two moons that are more than 99 percent the size of this month’s supermoon, and last year we had four.
So why was I out taking pictures of the full moon Sunday night? Because I think every full moon is beautiful, regardless of its size, and I take any opportunity to photograph it over my favorite landscapes. Which is also why each fall I schedule a workshop in Yosemite to coincide with the full moon.
Thursday night my Yosemite Autumn Moon workshop group photographed an 82% (of full) waxing gibbous (on its way to full) moon above Valley View at sunset. For Friday night’s sunset, from a quiet beach beside the Merced River we glimpsed through clouds an 87% moon rising just right of Half Dome. Saturday’s sunset found us beneath a magenta sky at Tunnel View to witness the 96% moon ascend between Sentinel Dome and Cathedral Rocks.
The workshop’s grand finale came Sunday night, when we gathered at the Half Dome vista on Big Oak Flat Road. Though I rarely encounter other photographers for any of my moon rise/set shoots, limited parking and tripod space here prompted me to arrive an hour before sunset. That turned out to be a fortunate decision, as within 30 minutes of our arrival the parking lot was brimming beyond full and photographers swarmed the nearby rocks like ants at a picnic.
With an hour to kill, I made sure everyone in my group was ready (but by now, this being our fourth moonrise, they were experienced veterans) and chatted with other photographers nearby. Comparing notes, it seemed that most (all?) of the other photographers had relied on apps like The Photographer’s Ephemeris and Photo Pills to plot the moon’s arrival location and time, while I was the only one clinging to my old fashioned topo map, scientific calculator, trigonometry plotting approach. (I do it this way because I’ve been plotting the moon since long before the apps were available, I feel like I can be more precise, and I enjoy it—not necessarily in that order.)
In the viewfinder of my Sony a7R Mark II, atop my tripod and armed with my Tamron 150-600 lens to enlarge the moon as much as possible, was the composition I wanted—assuming the accuracy of my calculations. The consensus among others seemed to be that the moon would appear from behind Half Dome’s right flank, anytime between 5:00 and 5:10 p.m. I stuck to my guns that the moon would show up at about 5:05, and that it would be straight over the top of Half Dome. While I saw this more as an opportunity to check my plotting method’s accuracy than a competition between methods, it was pretty thrilling when the moon popped into view right on schedule and on target. Take that, technology!
Since the moon didn’t appear until a full fifteen minutes after sunset, the extreme dynamic range (very dark landscape beneath a daylight-bright moon) made this an extremely tricky exposure for anyone (like me) not interested in compositing two images (one with the moon properly exposed, another with the scene properly exposed). To capture this scene with a single click, I closely monitored the pre-capture “zebra stripes” highlight alert in my a7RII and pushed my exposure 2/3 stop after the first hint of the alert appeared. To hedge my bets and give myself processing options, I varied my exposure 1/3 to 2/3 of a stop in either direction (an exception to my standard workflow because the moon is too small to register on the histogram).
The result was a scene that looked quite dark on my LCD, and a moon with no detail. No problem, I reassured myself, for my a7RII’s ridiculous dynamic range. This morning in Lightroom I adjusted the white balance, pulled up the shadows, and pulled down the highlights. In Photoshop I applied a moderate dose of Topaz DeNoise and did a few minor dodge/burn moves to get the image you see here.
One more thing
The size of the moon in this image has virtually nothing to do with the fact that this was a “supermoon,” and virtually everything to do with the fact that I was far enough away to be able to use a 600mm lens. Click below to read about how to capture your own big moon:
Click an image for a closer look and slide show. Refresh the window to reorder the display.
Posted on July 21, 2016
I’m a relationship photographer. By that I mean I’ve never been one of those photographers who expands his portfolio by adding new locations. Rather, I like to get a feel for a place, not just the where and when of its photo opportunities, but its history, geology, flora, and fauna. I much prefer digging deeply into one scenic area to visiting a large variety of scenic areas. This is a personal style thing, and I know my more deliberate approach would drive many photographers crazy, but I’ve learned that I’m rarely very productive on my first visit anywhere, and often not until I’m several visits in.
I’m probably several hundred (thousand?) visits into my Yosemite relationship, with no end in sight. But despite this extensive history, any moonrise above Yosemite Valley, regardless of the phase, still takes my breath away. Orbital geometry aligns Yosemite’s moon with different features as the seasons change, and I try to be there for as many moonrises as possible. Whether it’s the late fall and winter full moon hovering above Yosemite Valley, the summer crescent moon appearing from behind Half Dome, or the spring full moon rising above Bridalveil Fall, I just can’t get enough of it.
As with most of my Yosemite workshops, a planned highlight for this year’s April Yosemite Moonbow and Wildflowers workshop was a moonrise, this time the Bridalveil Fall full moon. Throughout the workshop we’d enjoyed a Yosemite Valley bursting with more water than I’d seen in several years, a dogwood bloom that was just about at peak, and a sky enhanced by an assortment of beautiful clouds.
When the moonrise day came and the clouds stayed, there were a few concerns for our moonrise. But knowing Yosemite well enough to understand that you can’t predict the conditions five minutes from now based on the conditions right now, I made sure we were in position with cameras ready (and fingers crossed).
Moon or not, the view up the Merced River Canyon that evening was beautiful, but when the moonrise time arrived and the moon didn’t, I scanned the clouds for hints of the moon’s glow. Though there was no sign of it, a little higher, and directly in the moon’s path, the clouds appeared thinner; higher still, actual stripes of blue sky gave me hope.
By the time the moon emerged, nearly ten minutes after sunset, the entire sky had taken on a rich magenta hue. The Merced River Canyon below had become quite dark, but my Singh-Ray two-stop hard-transition graduated neutral density filter held back the (daylight-bright) moon enough for me to give the canyon the light it needed. The final step for this image came in Lightroom and Photoshop, which enabled me to add a little more light to both the canyon and the clouds (which had been darkened along with the moon by the GND), and pull back the highlights in the moon.
One more thing
People ask me if I ever tire of Yosemite, and I can honestly answer, no. Part of keeping it fresh is the infectious excitement when the people I’m with witness something like this moonrise. (I don’t think this makes me unusual—most people get vicarious pleasure from the joy of others’ first experience of something that’s special to us.) This night the moonless pink sky was enough to thrill everyone, but when the moon poozed out, it became one of those once-in-a-lifetime moments for everyone in the group. That just never gets old.
Click an image for a closer look and slide show. Refresh the screen to reorder the display.
Posted on April 27, 2016
I spend much of my photography time chasing the moon. Most of my trips factor in the moon’s phase and location—usually to catch a full or crescent moon rising or setting above a particular landmark, and often to photograph a landscape by moonlight (full moon) or starlight (no moon). But sometimes the moon catches me less than fully prepared, and I need to improvise.
I enjoyed the January full moon with my workshop group in Death Valley and the Alabama Hills; in February my Horsetail Fall workshop group photographed a full moon rising above Yosemite Valley; in March I was in Sedona with Don Smith to photograph the full moon as it rose above Cathedral Rock and Oak Creek; and last week my Yosemite Moonbow and Wildflowers workshop group photographed the April full moon above Bridalveil Fall and the Merced River Canyon, then headed off to catch a moonbow in the mist at the base of Lower Yosemite Fall. And chasing the moon isn’t all about the full moon—already this year I’ve photographed several thin crescents in the Sierra foothills, and next week I raft Grand Canyon, where my group will (fingers crossed) witness a waning crescent moon just after sunset, and later that night photograph the canyon illuminated by nothing but the Milky Way and thousands of stars only visible in a moonless sky.
All this planning around the moon does indeed get me to many beautiful locations at just the right time, but sometimes the moon catches me in situations where, without the necessary knowledge at hand, I’m forced to think on my feet (and smartphone). Most recently was the unplanned moonrise added to last week’s Yosemite workshop. When the National Park Service opened Glacier Point about a month earlier than expected, I quickly inserted a Glacier Point sunset into the workshop but didn’t have time for anything more than a cursory moonrise check.
Beautiful clouds and light made our Glacier Point sunset a success, but as we were about ready to return to the warmth of the cars, the moon’s imminent arrival crept into the back of my mind. What I knew was that this night, from Glacier point the moon would be rising far to the right of Half Dome (out of the primary view), and probably just slightly too late to photograph effectively (not enough light to capture both landscape and lunar detail). Nevertheless, before packing up my gear I pulled out my iPhone to be certain we weren’t making the classic photographer’s mistake of leaving too early.
This won’t be on the test
Without a strong cell signal, I had to resort to apps that function offline. I started with Focalware, my go-to app for the sun’s and moon’s altitude and azimuth from any location on Earth. Next, now armed with the moon’s azimuth, I opened MotionX-GPS (with the map pre-downloaded) to plot its location relative to the current landscape, determining that it would emerge from behind Mt. Clark.
The final (and most difficult) piece of the puzzle was determining when the moon would appear. This is tricky because published moonrise times always assume a flat horizon—great if you’re on a ship at sea, but not so much anywhere else, and especially not in the mountains.
Using the topo info in the MotionX app, I determined that Mt. Clark’s elevation was around 11,500 feet. Knowing the Glacier Point is at 7,200 feet, I subtracted 7,200 from 11,500 and got 4,300 feet, the vertical distance between my location and the point where the moon would appear. Because the MotionX app also gave me the horizontal (as the crow flies) distance between me and Mt. Clark (about 8.2 miles, or around 43,300 feet), I had everything I needed to plug into my HP-11C (scientific calculator) app and compute the altitude, in degrees, that the moon would need to achieve before cresting the peak (thank God I stayed awake in trigonometry). With that information, it was a simple matter of returning to Focalware to see what time the moon would ascend to that altitude (appear above Mt. Clark).
There are apps that will do all this for me (PhotoPills and The Photographer’s Ephemeris are the ones I recommend), but they require connectivity, and the foresight to do the work when my signal is strong enough to download the maps. (Plus, I just like doing it my way.)
I never tire of this stuff
So, after less than five minutes of figuring, I was confident enough to tell everyone the moon would appear from behind Mt. Clark at 7:57 p.m., plus or minus two minutes. That gave us a couple of minutes to prepare a composition, and sure enough, right around 7:55, the clouds behind Mt. Clark started to glow; at 7:58, there it was and we were in business. In this case the thin clouds on the horizon subdued the moon’s brilliance just enough that I could give the foreground enough light without turning the moon to a white disk.
As often as I do this (sometimes I plot the moon just for fun, even though I know I can’t be there to enjoy it), few things thrill me more than my eyes on the exact point on the horizon at the moment the moon first nudges into view.
Understanding vs. knowledge
I know my process sounds complicated, but it really isn’t—in fact, plotting the moon this way doesn’t require any special insight beyond what most of us learned in high school. But it does illustrate something I constantly stress: the advantage of understanding over knowledge. When we know something, we can respond to a finite set of circumstances; when we understand something, we can reason our way to knowledge beyond our training.
One more quick example: A couple of days ago, I was scouting a potential sunrise location in the Columbia River Gorge. Because I’m reluctant to trust compass apps that point an arrow (or whatever) in a general direction, I pulled out Focalware and saw that tomorrow’s sunrise azimuth would be 70 degrees. Focalware also told me that the sun’s current azimuth was 253 degrees. Since I know that a (solar) shadow always points exactly 180 degrees from the sun’s current azimuth, I knew that my shadow was pointing directly at the 73 degree azimuth (253 minus 180), more than close enough to figure out where the sun would appear (in this case, farther north than ideal).
Whether it’s lunar geometry, exposure settings, depth of field, or whatever, understanding (and visualizing) a system’s underlying principles is always superior to memorizing its facts. And amazingly, it’s almost always simpler than we imagine. Since the position of the sun, moon, and stars are important to me, I try to visualize the celestial choreography.
Likewise, the more you can understand what’s happening when you adjust your shutter speed, f-stop, and ISO, the better prepared you’ll be to reason your way through difficult exposure puzzles, such as, I really need a lot of depth of field to get this tree and that mountain sharp, but the breeze is really blowing the leaves?, or, The exposure is perfect for this 20-second pinpoint stars image, but how can I do a 30-minute star trail shot of the same scene without changing the exposure?.