GoKawiilPALOMAR OBSERVATORY 200-inch Hale · 48-inch Schmidt
Palomar Mountain, California.
November 1949. Five thousand feet above the orange groves and the Navy airfields of San Diego County, the most ambitious map of the sky ever attempted is about to begin.
George Abell is a graduate student. From this observatory he will discover 2,712 galaxy clusters. But tonight, he just needs clear skies.
George is mapping a patch of sky. Each patch is photographed twice — once on a red-sensitive plate (fifty minutes), once on a blue plate (ten minutes). Two portraits of the same stars, in two colors of light, taken minutes apart.
For each exposure, someone must sit at the guide telescope and keep a star centered by hand.
Fifty minutes. In the cold. Night after night, for seven years.
After the exposure, the plate rides a dumbwaiter to the darkroom. Development must happen in absolute blackness. No safelights — the emulsion sees every colour of light.
1,872 exposures will be taken; only 936 pairs will pass inspection. The survivors go into drawers where they will sleep for decades…
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