The work of the Cassinis and Maraldis

It is intended that this part of the site will give a very short description of the impact on astronomy of the Cassini and Maraldi families.

As you will see, this has yet to be written… For those who are unfamiliar with the technique, the Latin text is known as ‘greeking’ and is placed in documents to create the effect of normal text.

The image to the right is of Saturn and its rings taken from the Cassini-Huygens spacecraft.

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Cassini’s map of the moon

Giovanni Domenico Cassini is remembered for – and his name is associated with – a large variety of astronomical and cartographical initiatives and discoveries as the preceding page on his life and work noted.

This illustration is of his map of the moon, organised in the period September 1671 to February 1679 when it was presented to the Académie des Sciences. The map was engraved by Jean Patigny. The geographer, Sebastien LeClerc was involved in the early stages of the eight year project, but the majority of the work was Patigny’s, based on Cassini’s observations made with the Giuseppe Campani lenses which he brought with him to Paris, and which were supplemented by a thirty-four foot telescope from Campani of Rome in 1672. Previously it had been believed that it was Le Clerc who designed and engraved the ‘Grande Carte de la Lune’, but it was much later confirmed to have been the famous Jean Patigny – 1647-1679 – according to Cassini IV. Jean Patigny spent eight years assembling his sketches for the map as he was only able to draw elements of the map from his observations at times when there were strong contrasts in the moon’s lighting and, of course, when it was visible.

Note that the map shows the moon upside down, as if it had been observed through an astronomical refractor, and is rotated clockwise by about 30°. The 53 cm diameter first edition map was published in 1679 and the illustration was considered to be a fine example of the engraver’s art. It was not until 1787 that a second edition was published, identical with the first though with ‘Carte de la Lune…de Jean Dominique Cassini’ added to the bottom rim. If the map is compared with a modern map of the moon it will be seen to be remarkably accurate.

The activities of the Académie des Sciences were very important and King Louis XIV took a keen interest in them. Here you may be interested to see an illustration of the presentation by Colbert of the members of the Académie to King Louis.

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The Moon Maiden

As mentioned previously, Giovanni Domenico Cassini moved from Italy to Paris where he married Geneviève Delaistre in November 1673, his name changing to Jean Dominique Cassini on his taking French nationality.

On inspection it can be seen that his drawing of the moon has, tucked away in the bottom right hand corner – shown in the illustration to the right within a small, white circle – what appears to be a portrait of a woman with long, flowing hair, known as the ‘Moon Maiden’. This is commonly thought to be a portrait of Jean Dominique’s wife, Geneviève. This illustration is a 1788 copy of Cassini’s original map and can be compared with the original above.

Confirmation of this suggestion has been tenuous. However, in 1678, Jean Dominique had commissioned a pen-and-ink portrait of his wife from Jean Baptiste Patigny, the son of the famous artist and engraver Jean Batigny, which gives considerably more credence to the possibility and, as noted above, was confirmed later by Cassini IV.