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SERIES — unspecified: HUM 9 Box 3 Identifier: HUM 9

Observations of Sun Spots, 1739-1743 Digital

Scope and Contents

Eleven-page notebook containing John Winthrop's handwritten observations and calculations. Titled by Winthrop "Observations of 'Spots' on ye Sun with ye Naked Eye," this is the first known record of his scientific observations and records what he saw while examining the sun "with an 8 foot telescope from 6 a.m. til sun set" on the Boston Commons and concluding with "a considerable aurora borealis" that night (April 20, 1739). It has been speculated that his reference to the aurora borealis in these observations may indicate that he recognized the interrelation of the aurora borealis and sun spots, a concept which was not definitively established until the mid-nineteenth century.

The notebook contains the page with notes on the sunspot for April 19-23, including two diagrams of the April 20 and April 22 sky, two pages with calculations of "y whole arc of 5d 6' divided into 70 parts," and six pages with astronomical calculations entered between November 21, 1740 and December 13, 1743."


  • 1739-1743

Researcher Access

The Papers of John and Hannah Winthrop are open for research.


.01 cubic feet (1 volumes)

Former call number

Formerly classified as HUG 1879.282 [Observations of "spots on ye sun with ye naked eye" and "for ye latitude of Cambr."

Immediate Source of Acquisition

Purchase, Minot Fund, November 17, 1880.

Repository Details

Part of the Harvard University Archives Repository

Holding nearly four centuries of materials, the Harvard University Archives is the principal repository for the institutional records of Harvard University and the personal archives of Harvard faculty, as well as collections related to students, alumni, Harvard-affiliates and other associated topics. The collections document the intellectual, cultural, administrative and social life of Harvard and the influence of the University as it emerged across the globe.

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