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The Royal Society: Science in the Making

Correspondence Explorer

Choose two people to view all letters between them.

Showing 28 letters from 1669–1677

28 letters from Jean Dominique Cassini; 0 letters from Henry Oldenburg

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Cassini states that he has pushed forward the ephemerides of the 'Medicean stars' (Jupiter's moons) A paper by Nicholas Mercator is attached which considers Cassini's geometrical and direct method for finding the anomalies of the planets. Figures and mathematical formulae are attached Oldenburg has written a note on the back of the paper about Dr Wren promising Collins the direct method for dividing the area of an ellipse and a table method for finding the length of the ellipse Mercator's paper originally published by the Journal des Scavans is printed in 'Philosophical Transactions', vol 5, no 57, p 1168 Read to the Royal Society on 16 June 1669

Reference number: EL/C1/50
1671

Cassini asks Oldenburg if he could employ Paul Boccone, a Sicilian botanist, who comes recommended by Gornia, physician to the Grand Duke of Tuscany Cassini's method (in English) for observing the altitude of the sun at St Petronius in Bologna is attached

Reference number: EL/C1/51

Cassini says that he sends a copy of his observations of the sunspots, then gives details of his observations of Saturn, and informs Oldenburg that Monsieur Picard was going to Tycho Brahe's observatory on the island of Hven in the Danish Sound to observe the lunar eclipse and the difference between the meridians and the height of the Pole Read to the Royal Society on 2 November 1671

Reference number: EL/C1/52
1672

Cassini sends his observations of Jupiter and of the comet which were published in the 'Journal des Scavans' He also compares the observations of the lunar eclipse at Aleppo with observations of the same eclipse made in Italy Read to the Royal Society on 24 April 1672

Reference number: EL/C1/53

Cassini provides his observations of a possible satellite of Saturn during October and November 1671; concerning Robert Hooke's observations of a lunar eclipse during September; Cassini gives his explanation of why Saturn looked round Read to the Royal Society on 11 January 1672

Reference number: EL/C1/54

Cassini thanks the Royal Society for electing him to the Fellowship and promises a paper on the ephemerides of Jupiter's satellites Read to the Royal Society on 26 June 1672

Reference number: EL/C1/55
1673

Covering note where Cassini sends a copy of his little book about the discovery of new satellites around Saturn Read to the Royal Society on 26 March 1673

Reference number: EL/C1/57

Cassini encloses a copy of his letter to John Flamsteed (see EL/C1/59)

Reference number: EL/C1/58

Cassini describes the telescopes that he has used to view Saturn Read to the Royal Society on 11 December 1673

Reference number: EL/C1/60

Discusses the diameters of the satellites of Jupiter and describes the telescope used to observe Jupiter and Saturn Encloses a copy of his reply to John Flamsteed (see EL/C1/61) Read to the Royal Society on 11 December 1673

Reference number: EL/C1/62
1674

Cassini gives his views about Robert Hooke's theory for the annual motion of the earth and then gives his own observations about this Partially printed in 'Philosophical Transactions', vol 9, no 105, pp 90-91

Reference number: EL/C1/63
1675

Concerning similarlities between the observations of the eclipse of the moon seen at Paris and London in June 1675 A list of observations is provided Printed in 'Philosophical Transactions', vol 10, no 117, p 390

Reference number: EL/C1/64
1676

Cassini states that he is sending an account of the future path of the sunspot (a published article in French, from an unidentified journal, entitled 'Description du Mouvement que doit faire dans le Soleil und Tache sur la fin de Novembre 1676' is attached) Cassini also says that Flamsteed's prediction for the conjunction of the moon with a fixed star was accurate and that he wishes to receive Flamsteed's ephemeris for the coming year

Reference number: EL/C1/65

Concerning a figure showing the path of the sunspot where Cassini states that he has added positions for its future path in December Figure no longer attached Cassini asks for the observations of the sunspot from English astronomers

Reference number: EL/C1/66

Concerning the mean time of the lunar eclipse and its magnitude giving the observations of John Flamsteed and Edmond Halley Printed in 'Philosophical Transactions', vol 11, no 123, p 561

Reference number: EL/C1/68

Concerning the occultation of a star in the 'lion's foot' by the moon in February Printed in 'Philosophical Transactions', vol 11, no 123, p 564

Reference number: EL/C1/69

Cassini makes calculations for the beginning and end of the eclipse of the sun, which occurred on 1 June 1676, because cloud obscured direct observations of it Figure in text

Reference number: EL/C1/70

Concerning observations of a spot seen recently on the sun and observations of the rings of Saturn (original figures in CLP/8i/32) Printed with figures in 'Philosophical Transactions', vol 11, no 128, p 689

Reference number: EL/C1/71

Concerning the observations of stars in the southern hemisphere made by Messrs Richer and Meurisse, and the meridian of St Helena island in the south Atlantic

Reference number: EL/C1/72

Cassini sends the position of the eclipse of the first satellite of Jupiter at the meridian of Paris in 1677 so that this eclipse can be observed at St Helena island in the south Atlantic in order to determine the difference between the two meridians

Reference number: EL/C1/73

Cassini sends calculations of the eclipse of the first satellite of Jupiter and some observations of the emersion of the first satellite from the shadow of Jupiter observed from Paris and Avignon

Reference number: EL/C1/74

Concerning the meridian altitudes of the sun observed at Caen, and the altitudes of the stars, so that the same might be observed at St Helena island in the south Atlantic Oldenburg added a note on the back of the letter about meridinal altitudes of the moon and fixed stars, and about the spots on the sun

Reference number: EL/C1/75

Concerning observations of the spot on the sun, and that the spots on Mars will be viewable soon as the planet is approaching earth

Reference number: EL/C1/76

Cassini states that the spot on the sun has returned for a third time, that he has been observing Mars to determine its parallax, and raises objections against Roemer's theory for the motion of light

Reference number: EL/C1/77
1677

Cassini gives thanks for the astronomical calculations computed by Oldenburg and Flamsteed which were sent to him and that his calculations for predicting the path of the sunspot were similar to those published by Flamsteed in 'Philosophical Transactions', and that he continues to use this theory for predictions

Reference number: EL/C1/78

Cassini gives his observations of the comet made in Paris Printed in 'Philosophical Transactions', vol 12, no 135, p 868

Reference number: EL/C1/79

Cassini gives his observations of the comet which were made near Madrid

Reference number: EL/C1/80

Cassini states that he sends two copies of the configuations of the satellites of Jupiter for August and September, one copy being for Flamsteed, and that he will produce the remainder of the configurations for this year. Observations of the principal spot on Jupiter and its discs are made with figure

Reference number: EL/C1/81