Messier was the ‘Ferret of Comets’

By Tom Burns - Stargazing

In 1751, real astronomers looked for comets, and Charles Messier longed above all else to be a real astronomer.

So, he hired on as the assistant to Joseph Delisle, of Paris, as a draftsman and clerk. His main job was to record Delisle’s telescopic observations.

Delisle was a gouty, crotchety curmudgeon. Working for him was no picnic. Messier did much of his work in a dank, unheated corridor at the College of France.

But in his spare time, he learned to use the telescopes. By 1754, he was doing a lot of Delisle’s observing for him.

And Delisle trusted him enough to give him an important assignment: to record the return of Halley’s comet.

Comets are hazy balls of light that occasionally develop beautiful tails. Up to the 17th century, it was generally believed that they were atmospheric phenomena like clouds.

Of all the objects in the sky, they alone moved unpredictably against the starry background. They appeared without warning, flaring to brief brilliance, apparently never to return.

However, in 1705, astronomer Edmund Halley had predicted the return in 1758 of a bright comet that came back every 76 years.

That would change everything. Comets would not be mere clouds but parts of our solar system. Like the planets, they would travel in long orbits around the sun.

Halley had died before the predicted return. It was up to skilled astronomers like Delisle to “recover” the comet as it sped from the depths of space back toward the sun. Because of Messier’s skill as an observer, Delisle gave him the job.

Night after night, Messier slowly moved his small, crude telescope across the sky, using charts prepared by Delisle. But the charts were wrong. Delisle had incorrectly plotted the path of the comet.

Eighteen grueling months after he had begun, Messier finally sighted the comet. His moment of glory was at hand! But sadly, the jealous Delisle refused to allow Messier to publish his discovery.

An even more crushing disappointment was to follow. Because of Delisle’s inaccurate charts, Messier had been beaten to the punch. A month earlier, a German astronomer had recovered Comet Halley.

Soon after, Delisle retired, and Messier was free to pursue his obsession. For the next 15 years, nearly every comet discovered was found by Messier.

In honor of Messier’s labors, the king of France bestowed on him the title “Ferret of Comets.” He deserved it.

Comet hunting is lonely, painstaking labor. The searcher uses a small telescope to slowly sweep the sky, hour after hour, in search of faint patches of light that were not there the day before.

As Messier swept the skies, he kept finding small, fuzzy patches of light. He would mistake them for comets until he observed them on a subsequent day and noticed that they didn’t move with respect to the background stars like comets did.

Messier decided to make a catalog of those fuzz balls and get them out of the way so that he could pursue his noble, lonely quest more efficiently. Over the years, he recorded the discovery of 110 such objects.

When it was finally complete, the list is made up partly of observations by other astronomers and mostly of objects he found accidentally as he tracked comets.

At the time, the list was more of a curiosity. Nobody cared much about those fuzz balls. Today we know better.

In middle to late March it is possible to see all 110 objects on Messier’s list in one night.

Experienced stargazers choose a night near the new moon to do just that, an event that has come to be called a Messier Marathon.

It is a grueling night. Thousands of amateur astronomers gather in rural locations far from the lights of cities. They set up their ‘scopes and arduously find these objects.

They marvel at brilliant clusters of stars. They revel in the glowing clouds of hydrogen gas where stars are being born. They observe the oddly shaped shells of gas around dying stars. And they stare with hushed awe at the pinwheels and ovals of light that are the galaxies, island universes of hundreds of billions of stars.

A marathon always ends when the sun rises, as tired and desperate astronerds try to pick off the last remaining objects before harsh sunlight destroys the gentle night.

As the dawn caresses their faces, you can see the exhaustion but also a wide-eyed glory. They have conquered the night and seen from beginning to the end the intricate texture of their universe.

The comets Messier discovered are mostly forgotten. Delisle is a footnote to history.

But on those long March nights, the name Messier is on the lips of countless stargazers as they sweep the sky for the objects he recorded. And because of him, those starwatchers know their home, their universe, in a way Messier could have never imagined. No one has left so great a legacy.

By Tom Burns


Tom Burns is director of the Perkins Observatory in Delaware.

Tom Burns is director of the Perkins Observatory in Delaware.