Featured Photographer - Robert Harvey ARPS

Digital cameras have opened up a whole new genre of our art; that of landscape photography at night. With the correct exposure, modern cameras can record much fainter objects than the eye can see, revealing a Universe of wonders. Robert Harvey BA ARPS shares his knowledge of landscape astrophotography and some of the techniques demonstrated in his recent book “Photographing the Heavens”.

For countless thousands of years, the night sky has been a common heritage of mankind. Over the last 144 years, since the invention of the electric light bulb in 1878, for many people that view has been lost. Today, most of the world’s population lives in cities, whose artificial lights obliterate all but the brightest stars. Travel into the countryside on a clear night and you can readily appreciate the view that city-dwellers miss. In a truly dark sky, you can see around 2000 stars. Arching across the sky between opposite horizons there is a faint band of light, the Milky Way. Landscape astrophotography is the art of combining elements of the night sky with suitable, and perhaps even dramatic, terrestrial foregrounds. The objective is to capture these scenes in camera, not to assemble them in Photoshop. The interest and challenge are in photographing astronomical subjects in situ.

A regular digital camera and lenses are sufficient to photograph celestial phenomena over an incredible range of scales. For example, the aurora borealis, or northern lights, occurs in the outer reaches of our atmosphere, around 100 km above the ground.

Aurora Borealis and Milky Way, Sycamore Gap, Northumberland

Aurora Borealis and Milky Way, Sycamore Gap, Northumberland

The best landscape astrophotography often results from a combination of good planning and good luck. This iconic sycamore tree grows right beside a remote section of Hadrian’s Wall, in a valley framed by the Whin Sill. I planned to photograph the bare tree against the night sky in midwinter, looking north with the Milky Way beyond. It was New Year’s Eve and I expect everyone else in the country was partying, while I was finding my way along the rugged Roman Wall in the dark.

When I got to my destination, I was surprised to see a faint glow, low in the sky beyond the tree. No-one lives in that direction, so where was the light coming from? When I photographed it, I realised I had an unplanned bonus - the elusive Northern Lights. Canon EOS 5D MK III, Rokinon 24mm f/1.4 lens. Exposure 20 seconds at f/2 and ISO 1600

Aurora Borealis, Lofoten Islands, NorwayThe characteristic green colour of aurorae results from collisions of solar particles with electrons in oxygen atoms. The energy from this interaction temporarily boosts oxygen electrons into a higher orbit (they are said to become “excited”). When the electrons drop back to their normal orbit, that energy is released in the form of light of a characteristic wavelength.

Aurora Borealis, Lofoten Islands, Norway

Aurora Borealis, Lofoten Islands, Norway

I waited four hours at this icy location for the aurora to appear. For a few seconds it was intensely bright over this mountain ridge. Swinging my camera round to capture it brought this cottage into my field of view. I liked the resulting composition but had no time to calculate exposure. I stopped my lens down to f/2.8 to increase the depth of field, so as to get the cottage in focus, and estimated a corresponding shutter speed. Canon EOS 5D MK III, Rokinon 24mm f/1.4 lens. Exposure 3.2 seconds at f/2.8 and ISO 1600

The most distant object we can see with our unaided eyes is the Andromeda Galaxy at a distance of 2.5 million light years (24 million trillion km). The light that reaches our camera sensor from the Andromeda Galaxy began its journey long before humans had evolved on Earth.

Obviously, these subjects are much fainter than daytime landscapes. The Full Moon is 400,000 times less luminous than the Sun, whilst the brightest star in the night sky is 40,000 times dimmer than the Full Moon. Exposures need to be adjusted accordingly so a wide aperture and/or high ISO are needed for most images. Shutter speeds are usually measured in seconds, rather than fractions of a second. A sturdy tripod is essential. To photograph at night, I always use manual control of aperture, shutter speed and ISO. As Earth rotates, objects in the night sky move across our field of view. This movement is imperceptible to our eyes but quickly shows in a photograph. To avoid stars turning into trails, shutter speeds should be a maximum of 20 or 30 seconds when shooting with a wide angle lens (16 to 24mm). Using a long telephoto (e.g. 400mm), Earth’s motion shows much more quickly and exposures need to be limited to one second. A rough guide is to divide 500 by the focal length of a lens to find the number of seconds of exposure possible without motion blur.

Star trailing can also be avoided by mounting the camera on a tracking device to compensate for Earth’s rotation. However, this is of limited use for landscape astrophotography as the foreground landscape then becomes blurred. A solution is to photograph the night sky with the tracker switched on and the foreground landscape with it switched off, then combine the foreground with the night sky in processing. (Continued on page 56.)

Geminid Meteor, Stonehenge, Wiltshire

Geminid Meteor, Stonehenge, Wiltshire

Meteors are grains of interplanetary dust that enter Earth’s upper atmosphere at typical speeds of up to 70 km per second. They are known colloquially as shooting stars, or more poetically as falling stars. Most are no bigger than a grain of sand. Their tremendous speed relative to Earth, which is moving at 30 km per second in its orbit, makes them highly energetic. Friction with air molecules causes meteoroids to burn up in a brief flash of light. Standing within Stonehenge stone circle on a frosty December evening, I made 125 consecutive exposures of 15 seconds each and captured this meteor heading towards Sirius on the 97th frame. Canon EOS 70D and EF-S 10-22mm f/3.5-4.5 lens. Exposure 15 seconds at f/6.3 and ISO 1250

Mars, Jupiter and Saturn viewed through Devil’s Den, Wiltshire

Mars, Jupiter and Saturn viewed through Devil’s Den, Wiltshire

A conjunction is the appearance of planets close together in the sky as seen from Earth. I captured this rare triple conjunction of Mars, Jupiter and Saturn through the aperture of a Neolithic dolmen at dawn in March 2020. Canon EOS 5D MK IV and Sigma Art 14mm f/1.8 lens. 20 seconds at f/2.8 and ISO 3200

Milky Way over Kynance Cove, Cornwall

Milky Way over Kynance Cove, Cornwall

Kynance Cove is close to England’s southernmost point and enjoys very dark skies, making it ideal for Milky Way photography. I visited on a night when the maximum visibility of the Milky Way core at 3.30am coincided with low tide, enabling me to capture a reflection of the Milky Way in a pool of water on the beach. Because there is no artificial light in the area, I needed an additional 8 minute exposure to bring out detail in the rocks and cliffs. Canon EOS 5D MK IV and Sigma Art 14mm f/1.8 lens. 12 light frames and 7 dark frames each of 20 seconds at f/2 and ISO 12,800, plus one light frame of 8 minutes at f/2 and ISO 3200 for the foreground.

“The Greatest Show in the Galaxy”, Minack Theatre, Cornwall.

“The Greatest Show in the Galaxy”, Minack Theatre, Cornwall.

Built into the side of a Cornish cliff overlooking the ocean, the stunning setting of Minack Theatre faces south-east. I had the idea of photographing the Milky Way rising centre stage at 3am in April. Canon EOS 5D MK IV and Sigma Art 14mm F/1.8 lens. 47 light frames and 17 dark frames each of 20 seconds at F/2 and ISO 6400, plus one light frame of 20 seconds at F/5.6 and ISO 1600 torchlit for the foreground.

Four Galaxies over Mesosaurus Fossil Site, Namibia.

I made this image in the exceptionally dark skies of southern Namibia, using the iconic silhouettes of quiver trees and dolerite rocks as foreground. From a latitude of 26 degrees south of the equator, this stitched panorama shows the arch of the Milky Way from the southern sky on the left to the northern sky on the right. In the southern celestial hemisphere, the brightest part of the Milky Way is the core of our galaxy, within which lies a supermassive black hole. In the far southern sky are the Large and Small Magellanic Clouds, independent galaxies outside the Milky Way. In the northern sky, a faint, fuzzy object is visible just above the horizon - the Andromeda Galaxy. Canon EOS 5D MK III and Rokinon 24mm f/1.4 lens. Stitched panorama of 12 frames, each exposed for 20 seconds at f/2 and ISO 3200

Four Galaxies over Mesosaurus Fossil Site, Namibia.

Star Trails over Wilton Windmill, Wiltshire

Star Trails over Wilton Windmill, Wiltshire

As Earth rotates, stars appear to circle around the north celestial pole, marked by Polaris which appears almost stationary in the sky. This movement is too slow to be noticeable to our eyes but the ability of a camera to make a sequence of consecutive exposures records it as star trails. Looking due north, my artistic concept was to capture star circles echoing the daytime rotation of the windmill’s sails. Standing beside the windmill, I illuminated it with a hand torch on the final frame. Canon EOS 5Di MK III and EF 16-35mm f/4L lens at 16mm.120 stacked exposures of 30 seconds at f/4 and ISO 3200

To optimise image quality, it is better to open the aperture wider, rather than to increase ISO or shutter speed. It is a wide aperture that enables the camera to collect the most light from faint objects, without motion blur or digital noise. An aperture of f/4 combined with an ISO of 1600 or 3200 is sufficient to photograph planets and stars, including many too faint to see with the unaided eye. However, most of my landscape astrophotography is done with a fast lens at an aperture of f/2, which is suitable for subjects such as aurorae and the Milky Way. Lenses at wide apertures need to be precisely focused in order to achieve a sharp result. This is an area where it is easy to make mistakes. Camera autofocus will work on the Moon but not on stars.

Manual focus can be achieved using Live View at 10x magnification. Select a bright star in the magnified field of view and turn the focusing ring until it appears as a point. After taking a picture, zoom in at 100% and check sharpness. If necessary, adjust focus and repeat.

To focus on a foreground object, shine a bright torch onto it and use either autofocus or manual focus (same procedure as for stars). When using a wide angle lens (24mm or wider on a full frame camera) at f/4, focusing on a foreground subject that is more than 5m away will give a depth of field extending all the way to infinity, so the stars will be acceptably sharp too. When shooting nearby foreground with a fast lens at f/2.8 or wider, I practise hyper-focal focusing. For example, a 24mm lens at an aperture of f/2 on my full frame camera has a depth of field extending from 5m to infinity, provided it is focused on a point 10m from the camera.

Good landscape images need a compelling foreground and landscape astrophotography is no exception. I like to use terrestrial elements with

Moon Rise, Glastonbury Tor, Somerset

Moon Rise, Glastonbury Tor, Somerset

There are just one or two days each year when the Full Moon rises far enough north to shine through the doorway of St Michael’s Tower on Glastonbury Tor. I worked out that, from a distance of 2.6 km, the height of the tower would appear smaller than the diameter of the Moon and it would take the Moon 22 minutes after rising to reach the elevation of the tower in the sky. My calculations were out by around 50m and when it rose, I had to run!

Viewed through a 400mm telephoto lens, the Moon moves quickly across the field of view and was centred behind the tower for only about one second. The presence of a figure in the doorway of the tower at that moment was pure luck. I wonder who he or she is? Canon EOS 7D, Canon EF 400mm f/5.6L lens. Exposure 0.3 seconds at f/22 and ISO 250

strong outlines that stand against the sky such as rocks, towers, windmills, natural arches and trees bare of leaves. Including a person provides a focal point and a sense of scale, which can instantly lift an astrophotograph above the ordinary. It is best to plan ahead, visit the location in daylight first and previsualise your composition. Ancient monuments are particularly evocative and, living in Wiltshire, I have a wide choice. Stonehenge and Neolithic long barrows are aligned to summer and winter solstices, so their connection to the cosmos is real. Foreground subjects can be shown in silhouette or illuminated by torchlight, moonlight (best when the Moon is around threequarters full) or even street lights.

For many astrophotographers, the plane of our galaxy, the Milky Way, is the most beautiful subject in the night sky. Appreciating and photographing it is only possible in the absence of artificial sources of light pollution and the Moon. Suitable locations include the 12 internationally recognised dark sky areas in the British Isles (www.darksky.org). The brightest and most complex part of the Milky Way is the core of our galaxy, which is visible from Britain low in the southern sky during spring (before sunrise) and summer (after sunset). I often photograph the Milky Way from southfacing coastlines such as Dorset and Cornwall. Looking out to sea, there is no light pollution (other than a few passing ships) to interfere with the view.

Because the Milky Way is faint, high ISOs are needed and images may suffer from digital noise. To get more light and less noise, one approach is to make a sequence of 20-second exposures which are then stacked in processing. The addition of dark frames (same settings with the lens cap in place) allows stacking software to identify noise on the sensor and subtract it from the finished image. If you become more interested in Milky Way photography, you may decide to venture overseas. As you travel south, more of the galactic core becomes visible. The southern hemisphere offers the best view, with the core high in the sky between March and September. The best viewing conditions are often found in deserts, where cloud cover is rare, atmospheric moisture is low and there is little light pollution. Stark desert landscapes such as rock formations and trees can make excellent foregrounds. While photographing landscapes at night, I recommend spending a little time away from your viewfinder to fully appreciate the night sky with your eyes. Experience the sense of wonder that must have been felt by generations of people before us.

Robert Harvey BA ARPS EFIAP CEnv CSci MCIWEM is a professional photographer and a chartered scientist. He founded Natural World Photography to share his enthusiasm for making innovative images of Earth and the Universe. His book “Photographing the Heavens”, available from www. naturalworldphotography.net for £25 including post and packing, shows you how to make stunning pictures of the night sky. Robert runs online astrophotography courses for the RPS (www.rps.org/what-s-on) and practical Milky Way photography workshops in Dorset, Cornwall and Namibia (www.naturalworldphotography. net/section844883.html).