The Mighty 200-Inch Hale Telescope In the late 1940s, a powerful new astronomical eye opened at the Palomar Observatory in southern California. The 200-inch Hale Telescope was twice as large as Mount Wilson's 100-inch telescope and could collect four times as much light. It remained the most powerful telescope in the world for over 30 years. With the 200-inch telescope, astronomers could peer deeper into the Universe than ever before and refine their estimates of how fast the Universe is expanding.
Prime Focus Spectrograph
	This instrument, called a spectrograph, combines the elements of a spectroscope and a camera: it spreads the light from a galaxy into a spectrum and records an image of that spectrum photographically on a glass plate. It was custom-made for mounting in the 200-inch telescope's prime focus cage, one of several points on the telescope where observing instruments can be attached. It was used for over 25 years. With this spectrograph, the most sensitive available in the early 1950s, coupled with the 200-inch telescope, the most powerful in the world, astronomers were able to study the faintest, most distant observable galaxies. Using the spectra images it produced, they were able to measure the expansion rate of the Universe with a precision never before possible. Prime Focus Spectrograph designed by Rudolph Minkowski and built by Don Hendricks in the Mount Wilson Optical Shop, 1950-51 Donated by the California Institute of Technology, Palomar Observatory
Other Featured Artifacts in this section of the exhibit: Lick Observatory Brashear Spectrograph

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