American astronomer (1906–1997) best known for discovering Pluto in 1930. ALS signed “Clyde W. Tombaugh, Professor of Astronomy Emeritus NMSU,” two pages, lightly-lined, 8 x 10.5, September 21, 1979. Very interesting letter concerning comets and their trajectories. In part: “Read about Kepler’s three laws in some astronomy text book. These three basically simple laws describe or define all trajectory motions in celestial mechanics whether for planets or for satellites, double stars, and rotation of galaxies…Jupiter has captured about 50 comets, its gravitational pull having decelerated a parabolic or hyperbolic comet into a closed elliptical orbit around the sun. Lexall’s comet orbit of 1757 had its orbit drastically changed when the comet chanced to plow thru Jupiter’s satellite system.” In fine condition. Pre-certified PSA/DNA and RR Auction COA.
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