Telescopes from the Ground Up

Era of Great Refractors

Harvard 15-inch Refractor

Telescope technology joins forces with photography

It was 1843, and a dazzling new comet was blazing through the sky. In Cambridge, Mass., the public turned to Harvard University for information. But Harvard didn’t have a telescope. Citizens and Harvard officials, now well aware of what they were missing, pooled their resources, bought some land, and hired two experts to build them a great telescope. Though the comet had come and gone, they were sure to be prepared for future cosmic events.

In 1847, they ended up with an excellent achromatic refractor with a 15-inch lens, which quickly began accumulating discoveries. It would be the largest telescope in America for 20 years.

Tick tock

Observatory Director William Cranch Bond, a watchmaker, brought his facility one of its greatest triumphs. Using clockwork to keep the telescope steadily focused on the Moon as it crossed the sky, he cast the Moon’s image on a photographic plate. After several seconds ticked by, he had the first picture of the Moon taken by a telescope.

• Harvard Refractor1847
• Naval Observatory1873
• Yerkes Refractor 1895

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