Question: Percival Lowell established the observatory after what American astronomer that discovered Pluto in 1930?

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Springfield Television: Springfield Television Corporation was a group owner of television stations based in Springfield, Massachusetts.  The company was founded by William Lowell Putnam III, who launched the company's first television station, WWLP, on March 17, 1953.  (Putnam was the son of politician and businessman, Roger Putnam.  He was also a former trustee of the Lowell Observatory, founded by his great-uncle, astronomer Percival Lowell.)

7553 Buie: 7553 Buie ( ), provisional designation 1981 FG, is a stony asteroid from the inner regions of the asteroid belt, approximately 3.5 kilometers in diameter.  It was discovered on 30 March 1981, by American astronomer Edward Bowell at Lowell Observatory's Anderson Mesa Station in Flagstaff, Arizona.  The asteroid was named after American astronomer Marc Buie.

Elizabeth Langdon Williams: Elizabeth Langdon Williams (February 8, 1879 in Putnam, Connecticut – 1981 ) was an American astronomer.  She graduated from MIT in physics in 1903 as one of their earliest female graduates, and was hired by Percival Lowell to help find Planet X.  She was the head human computer for Lowell in 1915, when her calculations led to the first captured image of Pluto, but she left the observatory before 1930 when Clyde Tombaugh finally realized the significance of this image.  In 1922, she married another astronomer, George Hall Hamilton.

Tombaugh Cliffs: Tombaugh Cliffs ( ) is a group of ice-free cliffs which stand at the north side of the mouth of Pluto Glacier and face towards the George VI Ice Shelf which occupies George VI Sound, on the east side of Alexander Island, Antarctica.  Photographed from the air by the Ronne Antarctic Research Expedition in 1947–48; surveyed by Falkland Islands Dependencies Survey from 1948 to 1950.  The naming by the United Kingdom Antarctic Place-Names Committee continues the astronomy related or celestial theme displayed in the toponymy of this area.  Clyde Tombaugh (1906-1997), American astronomer who studied at Lowell Observatory, who first discovered the planet Pluto in 1930.

A. E. Douglass: A. E. (Andrew Ellicott) Douglass (July 5, 1867 in Windsor, Vermont – March 20, 1962 in Tucson, Arizona) was an American astronomer.  He discovered a correlation between tree rings and the sunspot cycle, and founded the discipline of dendrochronology, which is a method of dating wood by analyzing the growth ring pattern.  He started his discoveries in this field in 1894 when he was working at the Lowell Observatory.  During this time he was an assistant to Percival Lowell, but fell out with him when his experiments made him doubt the existence of artificial "canals" on Mars and visible cusps on Venus.

Wrexie Leonard: Wrexie Leonard (September 15, 1867 – November 9, 1937), also known as Louise Leonard, was an American astronomer who worked as an assistant to Percival Lowell and published her observations of Mars.  A crater on Venus is named for her.

Clyde Tombaugh: Clyde William Tombaugh ( ; February 4, 1906January 17, 1997) was an American astronomer.  He discovered Pluto in 1930, the first object to be discovered in what would later be identified as the Kuiper belt.  At the time of discovery, Pluto was considered a planet but was later reclassified as a dwarf planet in 2006.  Tombaugh also discovered many asteroids.  He also called for the serious scientific research of unidentified flying objects, or UFOs.

William Henry Pickering: William Henry Pickering (February 15, 1858 – January 16, 1938) was an American astronomer.  Pickering constructed and established several observatories or astronomical observation stations, notably including Percival Lowell's Flagstaff Observatory.  He led solar eclipse expeditions and studied craters on the Moon, and hypothesized that changes in the appearance of the crater Eratosthenes were due to "lunar insects".  He spent much of the later part of his life at his private observatory in Jamaica.

Lowell Observatory: Lowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States.  Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark in 1965.  In 2011, the Observatory was named one of "The World's 100 Most Important Places" by TIME.  It was at the Lowell Observatory that the dwarf planet Pluto was discovered in 1930 by Clyde Tombaugh.

Lowell Regio: Lowell Regio is a region on the dwarf planet Pluto.  It was discovered by the "New Horizons" spacecraft in 2015.  The region corresponds to the Plutonian northern polar cap.  It is named after Percival Lowell who established the observatory where Clyde Tombaugh discovered Pluto.

Supporting paragraphs: Lowell Regio Clyde Tombaugh
Answer: Clyde Tombaugh