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Letter, from Henry Oldenburg to John Cruzado, dated at London

Reference number: EL/O2/161

Date: 03 February 1676


Transcribes Flamsteed's reply to Cruzado's letter concerning the prime meridian, the equation of time, the investigation of longitude, about a small instrument to aid observations with the accuracy of two or three minutes; that Jonas Moore had become a patron of astronomy and so possibly an observatory would be built.

Table attached with 'equations of apparent time (as mentioned above) the Earth's aphelion being in the seventh degree of Capricorn, which may serve throughout this century, interpolating the sun's true place'.

Reference number
Earliest possible date
03 February 1676
Page extent
8 pages

Creator name

Henry Oldenburg

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Henry Oldenburg, Letter, from Henry Oldenburg to John Cruzado, dated at London, 03 February 1676, EL/O2/161, The Royal Society Archives, London,, accessed on 13 July 2024

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  • Early Letters

    Dates: 1613-1740

    The archival collection known as 'Early Letters' is composed of original manuscript letters sent to, or collected by, the Royal Society from English and foreign correspondents.

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