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Nicolas-Louis de Lacaille (1713-1762) was one of astronomy's greats. He surveyed nearly 10,000 stars in the southern hemisphere and invented fourteen new constellations still in use today. He was always thoughtful in dealing with others, but he really liked the stars more than he liked people.

Nicolas-Louis de Lacaille

In the modern industrialized world, we are so well-documented that it's easy to forget that this wasn't always true. Most of the biographies I've seen of Nicolas-Louis de la Caille put his birth date at March 13, even some of those that are certain that isn't when he was born!

You see, he was baptized on December 29. This much is in surviving records, but unlikely for a baby born in March. With the high infant mortality of the time the custom was to baptize as soon as possible after birth. And this family had already lost several young offspring, so weren't likely to postpone a baptism.

About a hundred years ago, a historian who was a descendant of the Lacaille family studied the family papers and proposed a birth date of December 14. Others think he would have been baptized on the day he was born.

Now here's a constellation you don't see every night.


In fact, if you're in North America, Europe, North Africa or most of Asia, you won't ever see it, as it's not visible beyond 23 degrees north. It's Lacaille's constellation Reticulum, the reticle. And what is a reticle? A network of fine lines or fibres in a sighting device. In this case, it's the one in Lacaille's telescope eyepiece. He used it to help measure star positions.

There's a curious set of constellations in the southern skies. They don't represent exotic animals, heroic deeds or the foibles of ancient deities. They're composed of dim and nameless stars. Find out why Abbe Lacaille invented them, and take a quick tour.

Lacaille's Skies - Sciences

Here's NGC 2997, a stop on the tour of Lacaille's Skies. NGC 2997 doesn't sound very exciting, but in fact it's a grand design spiral galaxy. "Grand design" means that the spiral arms are prominent and well-defined. It's beautiful.

The galaxy is in Lacaille's constellation Antlia, which represents an air pump of the kind used by a 17th century physicist to study vacuums.

Another wonderful sight in Antlia the Air Pump is NGC 3132. It's a very complex planetary nebula. A planetary nebula is formed from the outer layers being thrown off by a sunlike star near the end of its life. In this picture, you need to look closely to see the star that formed the nebula. There's a bright star near the center, but it's the dim one nearby that's associated with the nebula.