In pictures: Hong Kong photographers show how to shoot night skies over city
We talk to two local experts on astrophotography who share tips on getting the best pictures of stars, galaxies and nebulas in our light-polluted city (and elsewhere)
When it comes to the galaxy we live in, travel photography doesn’t even require leaving home. Social media is flooded with all kinds of contrasting images of the night sky and the Milky Way, but they all have two things in common; patience on the part of the photographers, and – whisper it – some fairly simple photographic techniques. Taking images of the night sky really only requires four things: a DSLR (or compact camera with manual exposure), a tripod, clear and dark night skies, and dedication.
Using your widest angle lens, position the camera and tripod away from direct light, choose manual mode, then set the focus to infinity (or shine a bright flashlight on something about 20m away, auto-focus on that, then switch to manual focus). You can start with ISO 800, open the aperture as much as possible (f/2.8 or so, depending on the lens), and take an exposure for between 15 and 25 seconds.
While light pollution is a concern to anyone interested in the night sky, it doesn’t rule-out astro-photography. In fact, shooting the stars from within the city can lead to dramatic images. “I like taking night sky photos in suburban areas as I can put both the sky and the city lights into my composition, though it’s really challenging,” says Wong.
Chu is more interested in capturing specific constellations, so he adapts his composition accordingly. “I use a lot of low-angle shooting techniques, often lying on the ground because the stars are then easier to see,” he says. “I often teach the public about the stars, so I compose for the sky, and for the best angle to look at the stars.”
Although any image of a famous landmark or attractive composition with stars in the background can be awe-inspiring, there is one image that astro-photographers travel the world to capture; the Milky Way. Our own galaxy, home to at least 100 billion stars, is visible from earth as a dramatic arc across the night sky from northeast to south, but only at certain times of year. “The perfect time for photographing the Milky Way in Hong Kong is during the summer,” explains Wong. “We get clearer skies, and the bright core – which is the central bulge of the Milky Way, only displays in the summer night sky.”
Rich in star fields, nebulas and bright globular clusters, this area of the sky is a real hotspot for night sky photographers. “When I am taking still Milky Way shots, I normally use an ultra-wide angle lens and with the settings of ISO 3200, f/2.8 and 30 seconds exposure,” says Wong, who also uses an equatorial tracker that follows the rotation of the planet, thereby allowing much longer exposures. “If I use a tracker, the settings are totally different, maybe ISO 800, f/3.5 and perhaps a four-minute exposure,” he says, adding that imaging editing software like Photoshop and the astrophotography-centric PixInsight are useful for enhancing images. “I tend to give a cool blue tint to the sky and this gives a higher contrast to the orange-yellow dusty Milky Way,” he says. Chu prefers Lightroom, principally for the noise reduction and colour temperature tweaks it allows, though he underlines how important it is to take all night sky photographs in the RAW format, which makes post-processing much easier.
The time of year makes a big difference to what is visible in the night sky, so does your location on the planet. Move south towards, or even below, the equator and the Milky Way gets more and more prominent. However, when it comes to the universe, there’s no place like home. “I shoot stars all over the world, but I would still choose Hong Kong as my favourite place, because this is my home,” says Chu, who recently travelled to Mongolia to photograph the night sky. “Hong Kong has the world’s most famous urban light pollution, and the stars are slowly disappearing in my generation … with my photographs I want to evoke the forgotten starry night.”