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PrimeFocus

A wonderful phrase: Prime Focus. Technically it refers to the location where light hitting the main optical surface of a telescope forms an initial image, without further alteration by secondary mirrors or lenses. But the connotations of those words are far more magical. Astronomer George Ellery Hale wrote (in Harper's Magazine, 1928):

Starlight is falling on every square mile of the earth's surface, and the best we can do at present is to gather up and concentrate the rays that strike an area 100 inches in diameter.

The 200-inch Mount Palomar telescope was the result of Hale's lobbying and the generosity of the Rockefeller Foundation. This morning I chanced across the Palomar Observatory's pages of history ([1] and esp. [2]). They make marvelous reading.

For whatever reasons, astronomers tend to be long-lived. Jesse Greenstein (1909-2002) was one of the earliest observers at Mount Palomar; he joined the Caltech astronomy department in 1948, and spent cumulative months of his life in the Prime Focus cage of the big telescope, perched above the great mirror where he could change photographic plates and adjust instrumentation throughout long cold nights. See [3] and [4] for a memorial commentary in his own voice.

(I was lucky enough to meet Jesse in 1976 when I spent a night on Mount Palomar; cf. SeeingStars3 (14 Jan 2000), ...)


TopicScience - TopicPersonalHistory - Datetag20060317


(correlates: SeeingStars3, HumanGenomania, ChangingSelves, ...)