Top: A fish-eye view of the Selective Sequence Electronic Calculator, designed and built under Eckert's direction in 1946-48. It was one of the first large-scale computers, and the first to combine electronic computation with a stored program and capable of operating on its own instructions as data. Legend: "Large-scale computing equipment materialized at approximately the time when observational accuracy had begun to seriously exceed theoretical precision."   The SSEC was used by Eckert to compute the orbits of the five outer planets (shown) and that of the Moon; the latter calculations were used 20 years later to guide the Apollo missions.

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Frank da Cruz / fdc@columbia.edu / Columbia University Computing History / Sep 2003