Astronomer Clyde Tombaugh figures he has looked at 90 million stars in his long life.
But there is one moment - and one celestial body - that he remembers best. That was the day 66 years ago that he discovered the planet Pluto.It was Feb. 18, 1930, when Tombaugh, then 24, was poring over photographs of millions of stars taken through a 13-inch telescope at the Lowell Observatory in Flagstaff, Ariz.
At exactly 4 p.m., using an instrument called a Blink-Comparator, he found what he had been looking for - the long-sought, mysterious Planet X, as it was known to astronomers then. He verified the discovery, triple-checked his information, then ran to inform his superiors and fellow staffers.
"My heart was racing, boy oh boy was it. That was some day. Everybody was excited as the dickens," Tombaugh, now 90, told Reu-ters.
News of the discovery was not released to the press until three weeks later, at which time Tombaugh became a world celebrity. Newspapers around the world heralded his discovery, which was pretty heady stuff for a young man with no college training and not long off the farm from Kansas.
In 1928, Tombaugh had been hired at Lowell Observatory after he sent in sketches of Mars and Jupiter he had made by looking through a handmade telescope at his family's farm.
Scientists were so impressed with his skills that they hired him to join the team searching for Planet X, which astronomers believed existed but could not find.
They assumed that it was there because they had seen variances in the paths of Neptune and Uranus that could not be explained except by the gravitational pull of another celestial body.
Astronomers theorized that Planet X was located in a region of the sky called the Zodiac Belt. And that is where Tombaugh found it that day as he looked at photographs.
"Contrary to popular belief, I didn't discover Pluto by looking through a telescope. It's almost impossible to see through a telescope because it has the brightness of a candle seen from 300 miles," he said.
Instead, Tombaugh found Pluto by using a Blink-Comparator, which, with the help of photographs taken at different times, reveals objects that move among the stars.
After his great find, Tombaugh returned to Kansas to go to school at the University of Kansas. He continued to search for other planets while working on a master's degree.
Tombaugh found six star clusters, two comets, hundreds of asteroids, and galaxy clusters, but no more planets.
"During that period, I personally looked at more than 90 million stars - and that's a lot of stars, let me tell you," he said. Based on his research, Tombaugh is sure of one thing - no other planets exist in this solar system.
"If anyone wants to recheck my work, they are welcome to it," he said defiantly.
At the height of World War II, Tombaugh taught navigation and physics to Navy pilots. Then, in 1946, he moved to New Mexico to develop methods for tracking rockets under development at White Sands Missile Range. He eventually joined the faculty at New Mexico State University in Las Cruces, from which he is now retired.
Today, Tombaugh is in frail health and his celebrity has all but faded away. But that could change in the year 2003, when NASA plans to send space probes on a 13-year voyage to Pluto.