Beyond the Blue Horizon
Don't pack up your gear and leave just yet. Somewhere, out there, as the sun begins to set, lies an amazing image just waiting for you – beyond the blue horizon.
Living where I do in the Pacific Northwest, Mt. Rainier beckons large to the south. To many families, it makes a popular day trip destination. The main road up to the Paradise area is kept plowed year round. It's always amazed me though how the experience most visitors have of the mountain is so limited. They drive down after breakfast and make a day of it, being sure to leave in time to get back home before night. They see the mountain as a large, glaringly white snow covered peak against a blue sky and can't imagine it looking any other way. Few tourists see it at sunrise or sunset. Fewer still see it before sunrise or after sunset.
The same story can be told of many scenic destinations. On the coast, I'm generally out on the beach while it's still dark. At that hour, I often have the whole beach to myself. Shortly after sunrise, others start showing up. Yes, there are occasionally a few other photographers filtering in who also know the benefits of being an early rise, but it's remarkable how the beach traffic picks up once it gets to be daylight. The whole pattern plays out in reverse come sunset. Most everyone disappears come dinner time with only a few diehards out there after dark.
I and those few other dedicated souls out there know is that there are amazing images just waiting to be seen and photographed before the sun comes up and again after it goes down that evening. But sunset isn't just a single event, it's a process that starts with daytime and progresses through stages until we get to the black sky of night. The same is true for sunrise but in reverse of course.
The period known as civil dusk begins when the trailing edge of the sun crosses the horizon in the evening and continues until the sun is fully six degrees below the horizon. No, it's not fully dark yet by any means since the light of the sun refracts in the atmosphere. You won't be able to see the sun, but you can definitely see its effects in the beautiful band of orange along the horizon. By the end of civil dusk, most of the oranges will be gone from the sky. This is the end of what most people consider to be sunset, but things are really only just beginning. Civil dawn is the same in reverse. Generically, you can use the term "civil twilight" to refer to this period in the evening or morning. Images shot during civil twilight will generally show improved contrast and saturation over those taken before the sun actually sets since you won't have to contend with glare any longer.
Next comes what's called nautical dusk which lasts until the sun is twelve degrees below the horizon. The nautical dusk horizon transitions from orange into pinks and into purples. The colors will likely be changing quite rapidly and it can be hard to tell when you've reached "peak" color. Just when you think things couldn't get any better they do. Even at high ISO settings you're going to want a tripod to avoid motion blur.
Astronomical dusk follows and lasts until the sun's disk is eighteen degrees below the horizon. The only colors left at this point will be varying shades of deep purple and blue. By the end of astronomical dusk the sky will be the familiar black of night without any real color apparent. The brightest stars in the heavens will already be showing before things get to this point, with progressively more showing as the sky darkens. This can be a great time to shoot what appears to be night scenes while still having at least some foreground detail showing. A tripod is a must since exposure times can be quite long.
Most cityscape images are shot during astronomical twilight. Building and street lights will likely already be on, but the color that remains in the sky allows the buildings to fully stand out from the sky.
The time it takes for each of these to occur varies based on your latitude. At the equator, the sun goes straight up and straight down on the other side of the sky. The further north of south from this you are, the path of the sun goes at an angle. Since it still travels the same speed, it takes longer for it to pass through each successive degree on its ascent and decent. Think of the sides of a right triangle versus the hypotenuse to understand why this is. Of course, once you get really far north or south, the sun may never set at certain times of the year, or never rise at others. It goes at an even steeper angle near the north and south poles, but that arc curves around and heads the other way before ever making it to the horizon. I don't need to worry about that where I live, but I am far enough north that this phenomenon does have an impact. The length of the day, and thus the time from sunrise to sunset does vary quite a bit throughout the year. Days are long in summer and short in the winter.
If you look up the times for sunrise and sunset, they won't tell you the full story since such tables refer only to the point when the sun crosses the horizon, not the colorful times before and after. Plan accordingly if you want to be there for the full show. When in doubt, plan to arrive early and stay late.
Since there are 24 hours in a day and 360 degrees in a circle, the sun moves 15 degrees on its path when traveling straight up and down. That means you can approximate around 30 minutes (using a rough calculation) for each of these six degree increments. It will take longer at higher latitudes.
Magical things happen when the sun goes down. Even your eye can barely discern what's in front of you, your camera can record fully saturated color and detail with a sufficiently long exposure. You may be surprised at what you can end up with, given a bit of practice and care.
Mind you, I don't like getting up that early, but I do it for a reason. There's simply no other way to get the look of twilight without being there at twilight. If I had my way, I'd have a more leisurely breakfast and head out to photograph at a more civilized hour. But then I'd miss those beautiful images too.