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Partial Citation: A specialist at the NASA Jet Propulsion Laboratory, Jon developed and implemented the on-line Horizons system that is used by the international scientific community to generate accurate ephemeris information for the 450,000 currently known objects in the solar system. This includes the sun, planets, their moons, asteroids, comets, and many spacecraft... This system is used by observers, researchers, and mission planners to plan observations and track the targets of space and ground-based telescopes, as well as spacecraft. Since its inception in October 1996, the Horizons system has responded to more than ten million requests (on average, more than 2200 per day) received from 300,000 unique locations.