object was a faster moving asteroid and not a planet.
Astronomers spent years looking for Pluto. Clyde William Tombaugh was one of them, but he had special equipment. He had a telescope that could photograph a larger section of the sky, and he had a special device that would let him quickly see if an object had moved over the space of several days. With that device, in 1930, he found an object that shifted 0.12 inches in his photograph. He followed the moving light, and it traced the orbit of a distant planet. He had discovered Pluto.
