Birth of a Great Observatory

For many centuries, maps of the southern sky showed extensive blank areas — the Terra Incognita of the heavens. The year 1595: For the first time, Dutch traders set sail to the East Indies. At night, navigators Pieter Keyser and Frederik de Houtman measured the positions of more than 130 stars in the southern sky. Soon, celestial globes and maps showed twelve new constellations, none of which had ever been seen before by any European.

See this fascinating story from ESOCast.

The British were the first to construct a permanent astronomical outpost in the southern hemisphere. The Royal Observatory at the Cape of Good Hope was founded in 1820. Not much later, John Herschel built his own private observatory, close to South Africa’s famous Table Mountain.

What a view! Dark skies. Bright clusters and star clouds high overhead. Little wonder that Harvard, Yale and Leiden observatories followed suit with their own southern stations. But the exploration of the southern sky still took lots of courage, passion and perseverance. Until fifty years ago, almost all major telescopes were located north of the equator.

So why is the southern sky so important? First of all, because it was largely uncharted territory. You just can’t see the whole sky from Europe. A prominent example is the centre of the Milky Way, our home galaxy. It can hardly be seen from the northern hemisphere, but from the south, it passes high overhead.

And then there are the Magellanic Clouds — two small companion galaxies to the Milky Way. Invisible from the North, but very conspicuous if you’re south of the equator.

And then finally, European astronomers were hindered by light pollution and poor weather. Going south would solve most of their problems.

A scenic boat trip in the Netherlands, June 1953. It was here, on the IJsselmeer, that the German/American astronomer Walter Baade and the Dutch astronomer Jan Oort told colleagues about their plan for a European observatory in the southern hemisp