Rich Kowalski is a jovial fellow who loves his job but approaches it with a certain sense of dread.
Kowalski doesn't want to be the guy who finds the asteroid headed for Earth that will wipe out our species.
But that's pretty much his job description these days: Watch the skies. Sound the alarm.
"I don't want to be the one, but that is the name of the game," Kowalski said.
This month, Kowalski earned at least a footnote in the astronomy books by becoming the first to spot an asteroid before it crashed into Earth's atmosphere as a meteor - heady stuff for a high-school graduate who, three years ago, was driving tanker trucks.
Kowalski's discovery vaporized in a 1-kiloton explosion over Sudan before dawn on Oct. 7 - less than 24 hours after he spotted it from a 60-inch telescope atop Mount Lemmon.
That was a little asteroid - less than two meters long. If he ever finds a big one, say the size of the 6-mile-wide one that scientists think wiped out the dinosaurs 65 million years ago, Kowalski hopes to provide a little more notice. A couple of decades at least - preferably a century or more.
That might be enough time to do something. A rocket with a small nuclear device would be enough to nudge that baby off course, said Ed Beshore.
Beshore is survey operations manager for Catalina Sky Survey, funded by congressional mandate and run out of the University of Arizona's Lunar and Planetary Lab. The survey's astronomers have spotted lots of large asteroids, none, thankfully, on a direct collision course with Earth.
The sky survey and four other programs have, however, found 757 Near Earth Objects or NEOs. Their congressional mandate is to find 90 percent of those a kilometer (about 0.6 miles) or more in length and chart their courses.
The only one that really bears watching so far, said Beshore, is Apophis, which is scheduled to pass close to Earth in 2029.
There is no prediction of impact. Apophis is about 300 meters long and could cause "regional damage" were it to hit, said Beshore.
NASA's Jet Propulsion Laboratory at Caltech coordinates the work of all the NEO programs, two of which are based at UA's Lunar and Planetary Laboratory: the Catalina Sky Survey and Spacewatch, which has telescopes on Kitt Peak.
Catalina Sky Survey has recently found the lion's share of the objects - about 70 percent of those discovered in each of the past three years. "We have highly efficient software," said Kowalski, "all written in-house."
The asteroid he found earlier this month was no big deal, Kowalski said.
"Things are falling out of the sky constantly. This object ... was only newsworthy because we saw it."
The Sky Survey telescopes - the 60-incher atop Mount Lemmon, a smaller one with a wider field of view a few miles down the road at Mount Bigelow, and a third in Australia - typically find three Near Earth Objects per night, says Rik Hill, who was directing the 60-inch telescope on Mount Lemmon recently.
"I always joke with people that if I do the job to my utmost capability, I'll find the thing that'll wipe out our civilization," said Hill.
Hill sits at a computer terminal in a room next to the dome that houses the telescope. His job is to select a slice of the sky and photograph it four times, in 30-second exposures about 10 minutes apart.
That information is then analyzed by a software program that first discards the objects that haven't moved between exposures - stars. It can also weed out objects that have motions similar to those in the asteroid belt between Mars and Jupiter.
Then the observer weeds out things the computer might miss - cosmic rays or reflections creating false images.
Anything left over is set aside for another run of images, taken at the object's predicted path.
The Near Earth Object data are then sent to the Minor Planet Center at Harvard, which verifies it and posts the data on a Web site available to an army of astronomers across the globe, both amateurs and professionals.
"Anyone in the world can look at them within two or three minutes," said Kowalski.
Those extra eyes allow the program to quickly pin down the orbit of the objects, he said.
The importance of the prediction, said Beshore, is that it validates the technology that has been developed to watch the sky.
The CCD (charged couple device) cameras attached to the telescopes have it all over the photographic plates scientists used to use. They see more in a 15-second exposure than the old technology could record in four hours.
The computer programs, which disregard fixed stars and take into account previously cataloged objects, make it possible to zero in on those that might be problematic.
In the end, though, it's a judgment call, made by a human looking at a computer screen, and figuring out what that moving object is.
"The observer makes the final decision," said Beshore. "The human eye is still just a great discriminator. Having observers making that final determination of realness allows us to build these very sensitive systems."
Kowalski is enjoying his few minutes of fame, but mostly, he's just tickled to be working in the field he has loved since he was a little boy.
He's a self-taught astronomer, like many of those who do the follow-up work on his discoveries. He was an accomplished amateur and organized a Web-based home for astronomers interested in minor planets and Near Earth Objects 10 years ago.
Meanwhile, he worked a variety of day jobs: baggage handler, emergency medical technician, truck driver.
He still works two part-time day jobs as a photographer and flight instructor.
His real career starts when the sun sets - watching the sky for the big one that might hit us, hoping he never sees it.