7 Great Discoveries by Amateur Astronomers

By day, they might work as ministers, musicians and construction managers. But at night, they pull out their telescopes and scan the starry skies searching for cosmic phenomena.

The scar on Jupiter, the planet Uranus and the Hale-Bopp comet (from top left) are some of the greatest discoveries by amateur astronomers.

(ABC News)

And sometimes these amateur astronomers happen upon discoveries that rock the scientific community.

The latest example was just last week, when an amateur from Australia noticed an abnormality near Jupiter that experts lauded as one of the most significant ever by an amateur

"When it's something that's accessible, there is a community of people who think that it is wonderful and want to participate and sometimes make important discoveries," said Roger Launius, a NASA space historian.

While he said that many amateurs have been formally trained in astronomy, others have learned along the way, driven by enthusiasm.

Suzanne Gurton, education manager for the San Francisco-based Astronomical Society of the Pacific, said professionals have more technical background to analyze data but amateurs play an important role in the collection of it.

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"They all contribute to our knowledge of astronomy, to both the popularization and the science of astronomy," said Gurton.

Here are a few examples of those contributions.

Aussie Spots 'Scar' on Jupiter

Scientists around the world sat up and took notice last week when Anthony Wesley, the amateur Australian astronomer, reported to NASA that he was seeing something unusual in the southern hemisphere of Jupiter.

Something -- possibly a comet or meteoroid -- went slamming into the planet, was swallowed up in its atmosphere of ammonia and methane, and left a visible scar.

Scientists may never know the size of the object that hit Jupiter, and the planet itself will heal, but astronomers say the discovery is quite significant.

"The recent spot on Jupiter is one of the best accomplishments ever by an amateur astronomer ? it's of such importance," said Stephen Maran, press officer for the American Astronomical Society (AAS). In the mid 1990s, the Shoemaker-Levy 9 comet hit Jupiter and showed the world that planets, Earth included, were vulnerable to other space objects.

This recent finding, he said, shows that these occurrences don't just happen once in a lifetime but can occur regularly, even within a generation.

"It will be the public awareness that comes out of this finding that's all important," Maran said.