[2] He was the first of six children in the family with his sister, Esther being born 2+1⁄2 years after Clyde followed by his brother Roy in 1912, Charles in 1914, Robert in 1923 and Anita Rachel in 1929.

[3] Tombaugh's interest in astronomy appears to have begun when he visited the Yerkes Observatory in Lake Geneva, Wisconsin when he was 12 years old in 1918.

His uncle Lee also helped spark his interest in astronomy as he was an amateur astronomer who used a 3-inch (76 mm) diameter non-achromatic refractor telescope and gave him several astronomy-related books.

[10] While a young researcher working for the Lowell Observatory in Flagstaff, Arizona, Tombaugh was given the job to perform a systematic search for a trans-Neptunian planet (also called Planet X), which had been predicted by Percival Lowell based on calculations performed by his student mathematician Elizabeth Williams[15] and William Pickering.

Starting April 6, 1929, Tombaugh used the observatory's 13-inch (330 mm) astrograph to take photographs of the same section of sky several nights apart.

Tombaugh noticed such a moving object in his search, near the place predicted by Lowell, and subsequent observations showed it to have an orbit beyond that of Neptune.

In Roman mythology, Pluto can render himself invisible, his name's first two letters are Percival Lowell's initials, and it was proposed by an 11-year-old school girl.

The idea that Pluto was not a true planet remained a minority position until the discovery of other Kuiper belt objects in the late 1990s, which showed that it did not orbit alone but was at best the largest of a number of icy bodies in its region of space.

It has a relatively high orbital inclination, but at the time of Tombaugh's discovery of Pluto, Makemake was only a few degrees from the ecliptic, near the border of Taurus and Auriga,[21] at an apparent magnitude of 16.

[22] This position was also very near the galactic equator, making it almost impossible to find such an object within the dense concentration of background stars of the Milky Way.

In my 1949 sightings the faintness of the object, together with the manner of fading in intensity as it traveled away from the zenith towards the southeastern horizon, is quite suggestive of a reflection from an optical boundary or surface of slight contrast in refractive index, as in an inversion layer.

This suggests that the phenomenon involves a comparatively rare set of conditions or circumstances to produce it, but nothing like the odds of an interstellar visitation.

[29]Another sighting by Tombaugh a year or two later while at a White Sands observatory was of an object of −6 magnitude, four times brighter than Venus at its brightest, going from the zenith to the southern horizon in about 3 seconds.

"[31] Shortly after this, in January 1957, in an Associated Press article in the Alamogordo Daily News titled "Celestial Visitors May Be Invading Earth's Atmosphere", Tombaugh was again quoted on his sightings and opinion about them.

"Although our own solar system is believed to support no other life than on Earth, other stars in the galaxy may have hundreds of thousands of habitable worlds.

Tombaugh also told Hynek that his telescopes were at the Air Force's disposal for taking photos of UFOs, if he was properly alerted.

[34] Tombaugh's offer may have led to his involvement in a search for Near-Earth objects, first announced in late 1953 and sponsored by the Army Office of Ordnance Research.

Another public statement was made on the search in March 1954, emphasizing the rationale that such an orbiting object would serve as a natural space station.

[35] However, according to Donald Keyhoe, later director of the National Investigations Committee on Aerial Phenomena (NICAP), the real reason for the sudden search was because two near-Earth orbiting objects had been picked up on new long-range radar in the summer of 1953, according to his Pentagon source.

LaPaz had earlier conducted secret investigations on behalf of the Air Force on the green fireballs and other unidentified aerial phenomena over New Mexico.

[10] He worked at White Sands Missile Range in the early 1950s, and taught astronomy at New Mexico State University from 1955 until his retirement in 1973.

By 1965, Robert S. Richardson called Tombaugh one of two great living experienced visual observers as talented as Percival Lowell or Giovanni Schiaparelli.

The container includes the inscription: "Interred herein are remains of American Clyde W. Tombaugh, discoverer of Pluto and the Solar System's 'third zone'.

Adelle and Muron's boy, Patricia's husband, Annette and Alden's father, astronomer, teacher, punster and friend: Clyde W. Tombaugh (1906–1997)".

Professor Tombaugh (the one the station was named for) was working on a giant electronic telescope to photograph it, under a Guggenheim grant, but he had a special interest; he discovered Pluto years before I was born.