What’s so special about the Southern Cross?
"It was the time of the beginning of the New Zealand Marine, which then consisted of a single ship. In quite an informal way [Lieutenant] Markham was asked if he could suggest a distinctive flag. 'You have already the right', he replied, 'to fly the Blue Ensign, why not add to it the stars of the Southern Cross?' The suggestion was received with delight." So reads the biography of Sir Albert Markham, later to become famous as an Arctic explorer. But he is not our focus. Rather, we consider the question: why the response of "delight"? Why did this symbol, this Southern Cross, mean so much to New Zealanders of 1868 that it was natural to put it on the flag? What can it mean for us today?
A simple answer often quoted is that the Southern Cross represents the Southern Hemisphere. But there are other southern stars, so there is more to it. Let’s look back in time. To the ancient Greeks there was no Southern Cross, simply some stars that were part of the constellation Centaurus. But due to a wobble in the Earth’s Axis these stars have not been visible from Europe for nearly 2000 years. In the early 1300s the Italian poet Dante imagined himself passing through the Inferno at the centre of the Earth and coming out into the Southern Hemisphere. He arrives at the Island of Purgatorio, supposedly on Easter Sunday 1300. The first thing he sees is four bright stars near the South Pole, which he names for four natural virtues Justice, Prudence, Temperance and Fortitude. Dante’s stars may have been imaginary, but his poetry had a lasting influence. Two centuries later, on Easter Wednesday 1500, the Portuguese explorer Pedro Alvares Cabral discovered a Southern Hemisphere coast. He called it the "Land of the True Cross" after the four unfamiliar stars high overhead in the early evening. We now know this land as Brazil, and the stars as Crux, the Cross. Generations of Europeans sailing south would see this constellation rising out of the ocean ahead, with the long axis of the Cross always pointing south. Travellers took comfort from the thought that Christ was watching over them, so far from home. A world away, Polynesian sailors did not imagine the stars as a cross but they were well-known nonetheless. Visible as far north as Hawaii, and always located towards the south, they were part of a system of navigation used by the ancestors of Maori and Pacific Islanders to travel the vast distances across the ocean.
From the northern tropics, the Southern Cross is visible only briefly, rising and setting in a few hours. Further south the stars rise higher and higher in the sky until, from the Tropic of Capricorn down, the stars never set. New Zealand is one of only four nations in the world that can see the Southern Cross from everywhere in the country, all year round. (Yes, I’m excluding the Pacific Island territories we administer but that are not part of New Zealand proper.) The other three nations are Uruguay, Lesotho and Swaziland, whose flags don’t show the Southern Cross. So New Zealand has a unique reason to feel attachment to the Southern Cross and to claim it as a national icon. By contrast, our near neighbour Australia uses the Southern Cross on its flag, but the northern third of the continent cannot even see the stars at certain months of the year since they are below the horizon. Perhaps the residents of Darwin feel, at times, a sense of irony when they sing Australia’s national anthem "Beneath our radiant Southern Cross…".
The Southern Cross is the quintessential symbol of South-ness. Not only in name: it can be used to find the direction South, and thereby all other directions of the compass. It can also be used to tell the time. These facts may not be important in 2010 unless you are lost, but they still make a nice trick for 'showing off' or simply feeling connected with nature.
The angle the Southern Cross makes to the horizon depends on the time of night and month of the year. It can be sideways, even upside down. Imagine the Southern Cross is like the hour-hand of a clock, with the three 'top' stars at the tip of the hour-hand and the bottom star nearer the clock centre. Suppose you point your hand at the top star and move it along a line past the bottom star and out the other side. Stop at a distance a bit further than an adult’s handspan as seen at arm’s length. Then you will be pointing at the centre of the clock, a piece of blank sky called the South Celestial Pole. If you drop your hand to the horizon you will be pointing due South.
An alternative method of finding the Pole uses a line at right angles to the Pointers as well. Move your thumb and index finger along both lines at the same time, and where your thumb and finger touch is the South Celestial Pole.