On a clear night in most places in New Zealand, you can enjoy a clear view at the stunning southern night sky. Yet this treasure is one we've lost our connection with, says Naomi Arnold, author of the new book Southern Nights. She tells science reporter Jamie Morton how our light pollution is now threatening some of the darkest skies in the world – and why we should get out an appreciate it this summer.
How did you come to this book? Was it a story that, as a science journalist, you didn't feel had been yet properly told?
HarperCollins' New Zealand publisher Alex Hedley approached me in May 2017 with an idea for an approachable, illustrated introduction and guide to the southern night sky.
As I began researching I realised that much of New Zealand's fascinating astronomical history was hidden in academic journals and club histories.
There had been a few books about New Zealand astronomy and stargazing for a general audience such as Richard Halls' How to Gaze at the Southern Stars and Vicki Hyde's Godzone Skies.
But we wanted to produce a really beautiful book that would show off New Zealand astronomy to the general reader, discuss how important, fascinating and beautiful it is, and really highlight New Zealand astrophotography as well.
Aotearoa/New Zealand's heritage seems to be wedded to our night sky, from the celestial navigation used by those who came ashore in the first waka, to Captain James Cook and his astronomer Charles Green's observations of the transits of Venus and Mercury here two and a half centuries ago. Do you think this grassroots connection has been lost over time?
Yes. We don't need astronomy to help guide our day-to-day lives anymore, or to help us navigate.
Outside of science, the night sky has become a hobby for some and an occasional rural curiosity for the rest of us.
As cities have become more illuminated we've lost our view of the stars, and I think with that we've lost a really important connection with the environment, animals, and the rest of humanity as a result.
Once you consider that the night sky and its regular yearly pattern is the only thing in the natural world that won't change in our lifetimes, and that this experience is the same for everyone on the planet, you really start to get a sense of it being a roof over our shared humanity.
Knowing a bit about astronomy and the night sky is a powerful resource for culture, science, history, art, health, zoology and sheer beauty.
But there is a growing dark-sky movement that has recognised what is being lost, and it is awesome to see the recent resurgence in Māori astronomy, sparked by people like the University of Waikato's Dr Rangi Matamua, who puts in a huge amount of effort sharing his tatai arorangi knowledge via social media and lectures.
We have some of the darkest skies in the world and I would love to see more New Zealanders spend more time admiring them, which helps lead to their preservation from light pollution.
On that resurgence: we're seeing more people celebrating Matariki each winter, with some suggesting the Māori New Year be observed as a public holiday, or at least given more prominence than other occasions on the calendar like Guy Fawkes' Day. Is that something you'd like to see?
Personally, yes, but it depends on how Māori feel about their traditional astronomical knowledge being used in that way of course.
Some star lore is for tohunga only, but there are plenty of stories that local iwi use for general public consumption in their community celebrations.
Overall, it can't be a bad thing to have more New Zealanders learning about and respecting the vast store of astronomical knowledge Māori have and how it helped them survive in early New Zealand.
Along with that, it's also important for New Zealanders to understand how so much of that knowledge was lost through forced cultural assimilation and early Pākehā's imposition of Christianity over such "pagan" practices.
Matariki is also great for introducing kids to space - and Guy Fawkes is lame.
Do you suspect that our knowledge of the southern night sky has been somewhat confused by references in American TV and film to features of the northern night sky, such as the Big Dipper or the North Star?
Definitely - we have a big telescope at home now and we have been taking guests to observe objects in the summer night sky.
Many people ask about the Big Dipper and the North Star, but you can't see them from New Zealand.
We don't have a really handy star to almost exactly pinpoint the south celestial pole and find south, as the North Star does in the northern hemisphere; instead we have a patch of dark sky rather unceremoniously called the south solar pit.
But I do think the Southern Cross holds its own as a powerfully culturally relevant constellation, and it's fun to show people and kids how to use that to find south, too.
Compared with the Northern night sky, what's above us has only been explored relatively recently. Why is this?
New Zealand was inhabited much later than the rest of the world, and much of the southern skies were unknown to Europe until explorers began to venture down here, map them, and publish.
Amateur astronomy has always been in respectable health in New Zealand and astronomers have made important contributions to global knowledge, but in terms of professional astronomical scientific research there simply weren't as many professional observatories in the southern hemisphere compared to the northern, despite New Zealand's position on the planet being an important point in continuous global observation.
In 1960, for example, there were only 10 observatories set up in the entire southern hemisphere, compared to 88 in the northern hemisphere, and none of those were in a site carefully chosen for the quality of their skies.
Even if they were, southern hemisphere telescopes only had the power to collect 10 per cent of the light of northern ones.
Eventually, efforts were made to address this including setting up the University of Canterbury Mount John Observatory in Tekapo, in collaboration with a university in the United States.
At the last check, light pollution levels above New Zealand weren't too bad. Based on land area, about three quarters of the North Island and 93 per cent of the South Island had night skies that were either pristine or degraded only near the horizon. Still, is there a danger we could lose this?
Yes, because wherever people go, they bring light.
Humans love extending their daytime hours with artificial light. I think dark-sky preservation should be enshrined in law and building codes by using appropriate outdoor lighting for roading, homes, and commerce.
This includes colour temperature - the warmer the better, for animal and human circadian health - luminosity, light placement, shielding, and considering if a light is needed at all.
Once a light is installed, it's hard to remove it.
We've been hearing a lot more about these dark sky reserves, and pushes to create them around New Zealand. Can you tell me exactly what these are and their importance and benefits?
There are around a dozen groups in New Zealand that are working towards dark-sky accreditation through the International Dark-Sky Association.
This means they are actively preserving and celebrating their night sky.
There are several levels of accreditation, including dark-sky sanctuaries - Great Barrier Island and Stewart Island are our two existing ones - reserves like Aoraki-Mackenzie, parks, and so on.
They are full of wonderful people who are really passionate about astronomy and all the benefits that dark skies can bring New Zealand in terms of human health - too much light at night has been implicated in a host of diseases from depression to cancer - tourism, cultural preservation, education, science, and beauty.
Preserving a night sky doesn't mean we'll have to all go about in dimness, but it means making smarter use of the light we do have, wasting less electricity, and sending less light straight up into the sky.
For Kiwis keen to learn a little more about astronomy and our sky, stepping out into the backyard and taking a look upward might seem a bit daunting. Where should we start? Would you recommend a few trips to the local observatory before we start star-gazing?
You can go to an observatory to check out their different programmes, but it's great to learn about the stars and constellations visible from your own backyard and learn how they move in relation to your back fence, for example.
It's a good way of beginning to picture how it all works. You can use your fence and the neighbour's roofs as your own personal Stonehenge.
If you want to go out tonight then I'd just download an app like Night Sky, SkyView, or SkyGuide - there are heaps of them - and get pointing. They have dark modes so you don't lose your night vision.
Those apps really help in visualising how the universe works. A pair of binoculars can help you see more.
The app Stellarium is really cool too - it's a desktop programme that lets you zoom forward and backward in time, seeing how the planets and stars rise and fall.
If you want to see deeper into the sky, the folks at AstroNZ - an offshoot of the Auckland Astronomical Society that reinvests all the funds it makes back into the business and supporting astronomy and science education throughout New Zealand - will set you up with a decent telescope at a reasonable price.
You can find your local dark-sky preservation society or start one if there isn't one.
You can go along to a star party organised by the astronomy section of your local science society and helpful people with telescopes will show you cool stuff through them like clusters and nebula.
The Royal Astronomical Society of New Zealand has email lists and newsletters, and I'd also follow Living by the Stars with Professor Rangi Matamua on Facebook to learn more about Māori astronomy.
He has 20,000 followers so you will be in good company if you have any questions.
A final question: what are your favourite things about our night sky?
Overall, the fact that it is always there.
It's so rewarding to go out on a dark night and lie down with a blanket and spend a few minutes sinking into wonder, considering that you're a passenger on a planet whipping through space, and that each of those bright white dots is a little sun or planet, and that the more you learn, the more questions you have, and then you're galvanised to find out more.
Everyone has felt at least moments of this at times.
It's refreshing to consider the unimportance of your life and think about how our ancestors used the sky to live their lives, and what people on the other side of the world are doing right now.
Last night when we went out with the telescope, most of the planets had dipped below the horizon and it's simply just a cool thing to think about where they were right then in relation to yourself and when we could see them again, turning the Earth in your head like a Rubik's cube, looking forward to Scorpius and the galactic core of the Milky Way coming back into view as winter comes on.
It's like a brain and perspective reset. And spending time without light under a dark sky is also excellent for bringing on that nice, sleepy, camping-holiday type evening daze that can be so elusive in our normal busy lives.
Southern Nights, by Naomi Arnold, (HarperCollins, $65).