Skip to content

Please be aware that some material may contain words, descriptions or illustrations which will not reflect current scientific understanding and may be considered in today's context inaccurate, unethical, offensive or distressing.

Letter, from Henry Oldenburg to Jean Cassini, dated at London

Reference number: EL/O2/55

Date: 26 August 1671


That Brouncker had been shown Cassini's paper on the sunspots; encloses pages of Boyle's observations of the sunspots made in 1660; concerning Huygens' 'Systema Saturnium'; concerning observations of the occultation of Saturn by the moon by Hevelius; postscript that Monsieur Picard had observed the sunspots in 1661 and that some English astronomers had just observed a sunspot on 25 August 1671

Reference number
Earliest possible date
26 August 1671
Page extent
3 pages

Creator name

Henry Oldenburg

View page for Henry Oldenburg

Use this record


Henry Oldenburg, Letter, from Henry Oldenburg to Jean Cassini, dated at London, 26 August 1671, EL/O2/55, The Royal Society Archives, London,, accessed on 25 July 2024

Link to this record

Embed this record

<iframe src="" title="Letter, from Henry Oldenburg to Jean Cassini, dated at London" allow="fullscreen" frameborder="0" width="100%" height="500px"></iframe>

Related Fellows


Explore the collection

  • 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.

    View collection