IF you’re an astro-geek, this was as good as it gets.

Around the time of the 40th anniversary of the Moon landing last week, an amateur astronomer in Australia detected evidence that a comet had collided with Jupiter, leaving a bruise the size of Earth. This was just days before the longest solar eclipse the world will see this century, in Asia  and in the same summer as a new “Star Trek” movie, no less.

For backyard stargazers, it hasn’t been this delicious since Pluto was demoted from planet status.

“When I got up and saw the reports coming in, it was the most exciting thing I’ve seen for years,” said Steve Fuqua, a sixth-grade teacher and amateur astronomer in San Jose, Calif., who first heard the news in an e-mail alert from an astronomy group. Over the next few days, he was constantly online monitoring what other amateurs were seeing as the earth and Jupiter rotated. When amateurs from Europe to Hawaii started reporting their own glimpses of the black spot, the chatter lighted up around the globe, he said.

By day, Mr. Fuqua, 56, kept in steady e-mail contact with students in his astronomy club to discuss the significance: Would a blow like this to Earth wipe out civilization? By night, he would set up his telescope in front of his house at 3 a.m., hoping to make discoveries that he could share with the world. No luck, he said: “My humble little telescope just wasn’t up to it.”

He did score one minor victory, though  he managed to get his wife, Ping, out of bed at 4 a.m. to take a look.