The night fantastic!
Dazzled by the night sky? Nightscape expert Ollie Taylor explains how to capture the wonders of the universe
Many of us are fascinated with the vast enormity of the unknown – space! Who hasn’t paused for an instant to gaze at the stars, totally lost in awe, transfixed by a moment in time that seemed as if it lasted forever… But how do you capture these magical night-time vistas on your camera? Well, armed with your Nikon DSLR and tripod, and perhaps a Thermos full of something warm, and you’re halfway to becoming a star-shutterbug.
Advances in DSLR technology over the past decade have helped push the lowlight and night photography boundaries, opening the genre to the masses. With such a fascinating subject, and the possibility of creating such mind-blowing images, it’s no wonder nightscape photography has become one of the fastest growing genres of photography. And this feature aims to encourage you to venture out into the dead of night and grab a slice of cosmic action.
Planning is vital to the success of any nightscape shoot. The first consideration is the weather – there’s little point heading out if the sky is full of dense, impenetrable clouds. Naturally the most favourable weather to venture out in is a clear night under a star-studded sky! However, a light scattering of cloud can also work, and can actually add real impact to the image.
When to shoot
The spring, summer and autumn months are renowned for shooting the Milky Way, but winter is the best season for clarity, as haze and mist are not as prevalent as they are on warm days and cold nights. And, of course, the night falls earlier, and remains darker for longer.
But astronomy-related subjects can be photographed all year round, with
different items of interest in the heavens at different times in the shape of planets, constellations, meteor showers, the position of the International Space Station, and, naturally, the moon. Phenomena such as dancing auroras and zodiacal light can be captured with a little careful planning – along with an element of luck.
It’s a misconception that the Milky Way can only be photographed during certain months, as it can be seen throughout the entire year. The most prominent part, however, the galactic core (the part we see when looking toward the centre of our spiral galaxy), is only visible at certain times of the year – and certain times of the night. In the southern UK, it can be photographed from late-February to mid-October, although the shooting window is relatively small, with much more time from April to September.
In the northern hemisphere, the centre of the Milky Way rises to the southeast in early spring, due south by summer, and to the southwest by autumn. Early spring is a favourable time of year, as the arc of the Milky Way sweeps low across the horizon making for easier panoramas – it also makes for a sleek diagonal across a single-frame 3:2-ratio landscape image. Closer to the equator in the northern hemisphere, such as from Greece, the annual time the core is visible extends slightly, and a greater section of the centre is also visible in the summer as it rises over the horizon in its entirety. Whereas in the UK, we only ever see part of the centre of the galaxy, situated on the horizon.
Great heavens above
Twilight, the period of darkness when the sun dips below the horizon but there’s still some light in the sky, actually has three distinct phases – civil, nautical, and astronomical – determined by how far the sun is below the horizon. The waxing and
waning moons can look far better during civil and nautical twilight. However, to get the best detail and brightest stars within the night sky, you’ll need to wait for total darkness, when the sun is more than 18 degrees below the horizon.
If aiming for the stars and the Milky Way, understanding lunation – the different phases of the moon and its position in the sky – is vital. The light of the moon will easily overpower that of the stars, so you need clear, moonless nights. The times of the new moon, and of the moon rising and setting, have to be cross-referenced with the twilight times to indicate prime
dates and hours of visibility for a the clearest views of the Milky Way.
Geographical location also has a drastic impact. The higher the latitude, the more adverse the effects of the solstice on nightscaping – twilight lingers all night, leading to the absence of total darkness, and, in turn, a large percentage of the stars.
There’s an app for that
Thankfully, working out the best times to shoot the stars has become much easier due to the plethora of apps and websites. PhotoPills has emerged as the number one app for planning out shoots involving the Milky Way and moon (alongside many other useful features). It enables annual planning and global geographical positioning, and allows the user to work out lunar cycles and galactic centre times at their location.
The Starwalk app is invaluable for showing the positioning of planets, constellations and meteor shower notifications, and allows the user to move through time to plan out what will become apparent in the night sky at the chosen location. Augmented reality, superimposing a graphical representation of the night sky over the view from the camera, gives an indication as to exactly how the night sky will complement landscape features as a backdrop. Aurora apps, such as Aurora Forecast, and UK Aurora Watch, aid in chasing the Northern Lights.
Websites that show light pollution, such as www.darksky.org, can help you work out if your chosen location will be dark enough, while time and date websites can display an entire month’s lunar and solar activity on one page, providing a very useful visual reference to plan out multiple shoots.
Essential kit
The most essential item you’ll need for nightscapes is a good quality tripod.
Shooting in the dark means extremely long exposures, so a rock-solid support is an absolute must have.
A programmable cable release is very handy, as it will enable you to set the length of bulb exposures, or even multiple exposures for star trails.
While an entry-level camera and kit lens can yield decent results, this is one area of photography where good glass greatly improves results. A super-wide-angle lens enables you to capture a greater slice of the night sky, and fast lenses enable you to shoot at very wide apertures, allowing you to capture precious light in a
shorter time. Lens anomalies really do show up in night photography – stars are quite likely to take on unusual shapes in lowerquality optics, so a top-quality, fast, wide-angle lens, such as the Nikon 1424mm f/2.8, is desirable. A full-frame camera’s sensor has larger individual photosites than that of a crop-sensor model, capturing more light and thus having better lowlight performance, and less image noise at high-ISO settings.
Specialist panoramic heads enable vast nightscape scenes to be stitched together. Whereas star trackers and equatorial mounts pivot the camera precisely with the
rotation of the earth. These grant really serious astrophotographers super-long exposures of celestial bodies with minimal movement blur occurring as the camera takes extended shots of the nightscape.
Composition
You’ll need to think like a landscape photographer when it comes to composition. Captivate the viewer by combining land and sky elements effectively. Composition should follow the same principles as general landscape photography; while it may be tempting to angle the tripod head upwards so the lens’s field of view attains an enormous amount of sky, only incorporating a slither of shadowy foreground will not complement empty gaping skies, no matter how fascinating the shimmering stars.
Focus for sharp stars
Above all else, it’s vital that the stars are pin-sharp. You’ll have to focus manually – autofocus just won’t play ball in the dark. First set the focus ring to the infinity mark, along with a wide open aperture, then ramp up the ISO to as high as possible. In Live View mode, scroll around the sky until the brightest star available is in the centre of the LCD, and magnifying it with digital zoom. Tweak the focus ring manually, until the star is as sharp and refined as possible, almost representing a pin head.
Exposure
Generally, use ISO ranges from ISO32008000, though ISO4000/5000 usually offers the best compromise between brightness and image quality. Most f/2.8 lenses can be shot with the aperture wide open, but you’ll need to pay particular attention to the stars around the corners and edges of the frame, especially if you’re using longer focal length lenses;
often, they’ll need to be stopped down a little to ensure better image quality.
Shooting the aurora requires much lower ISO settings. It depends on how intense the auroral display is, with ISOs usually ranging from 200-1600, depending on your shutter speed. Likewise, harsh moonlight can lead to a drastically lower ISO setting being required, usually ranging from 200-1000, depending on cloud cover.
Calculating best shutter speed
There are calculation methods, such as the 500 Rule (see page 21), to help work out the best exposure for capturing stars without trailing, however, it’s not always perfect, as it was devised as a guide for using 35mm film when crop factor and sensor resolution wasn’t a consideration. Cameras that pack in a huge number of megapixels, such as the Nikon D850, may record movement when those with a fewer megapixels look sharp.
As a rule of thumb, work on the basis that an average DSLR with a wide-angle lens will manage an exposure of about 20 seconds before the stars visibly start trailing. So start at 20 seconds, then check the frame for trails, if there is no trailing, try a frame at 25 seconds; if there is a trail, reduce shutter speed again until the stars look pin sharp.
The aurora requires a slower shutter speed to avoid burning out highlights but long enough to capture the detail within the display’s movement – between two and eight seconds are common speeds for the Northern Lights.
Unless shooting directly towards the moon, use the same length of shutter speed as you would the stars. However, a faster shutter speed is required to retain asharp moon within the landscape, such as a waning or waxing moon. You’ll also want a much faster shutter speed to capture surface detail when taking an exposure through atelephoto lens, of around 1/4 sec.
Exposing for the land
Shooting the sky and land all in one shot will lead to a very grainy foreground due to the high ISO settings needed, and the exposure required for a bright starry sky usually won’t match the ideal settings for the land below. So customary practice is to first take an exposure for the sky, then take a second exposure for the land, stopping the lens down to between f/4 to 5.6, and bringing the ISO down to a much cleaner ISO100-1000. Next, light up the foreground with a torch to ensure focus, then commence a prolonged exposure, adjusted to anything from five minutes, to half an hour…
Throwaway frames
But exactly now long should this exposure for the land be – and how do you compose in total darkness in the first place? The answer is to use your camera as your eyes to get an idea of the composition you want. Obtain focus, then adjust the ISO as high as it will go and open the lens to the widest f-stop and take a shot. The resultant frame will be extremely noisy, but should be bright enough for you to see the composition and judge the brightness. Recompose until reaching
a satisfactory composition and adjust the shutter speed for a nicely exposed foreground. You’ll need to do a bit of arithmetic to work out the ideal exposure time; for every stop you close the shutter and reduce the ISO, you’ll need to double the shutter speed.
A body with high ISO capabilities, and a fast lens, will drastically reduce shutter time when producing these ‘throwaway frames’, which can be deleted in post-production.
ong exposure noise reduction
The camera sensor will heat up during any long exposures, thus generating hot pixels in the thousands. This is made worse because of the sheer darkness of the scene.
The best way to combat this is to turn on the your Nikon’s ‘Long Exposure Noise Reduction’ function. This takes a second ‘dark frame’ using identical exposure settings but without opening the shutter. This will result in the same hot pixels in an otherwise completely black image, which can then be automatically removed. This doubles the already lengthy exposure time, but you can safely pop the lens cap on, pack your camera in your bag and head for home while the shot is being taken, for some well-deserved shut-eye!