Giovanni Domenico Cassini

[Ptah]

http://en.wikipedia.org/wiki/Giovanni_Domenico_Cassini

Giovanni Domenico Cassini (June 8, 1625 – September 14, 1712)
was an Italian/French mathematician, astronomer, engineer, and astrologer.
Cassini, also known as Giandomenico Cassini or Jean-Dominique Cassini,
was born in Perinaldo, near Sanremo, at that time in the Republic of Genova.

<snip>

Cassini was the first to observe four of Saturn's moons, which he
called Sidera Lodoicea, including Iapetus, whose anomalous variations
in brightness he correctly ascribed as being due to the presence of
dark matter on one hemisphere (now called Cassini regio in his honour).
In addition he discovered the Cassini Division in the rings of Saturn (1675).
He shares with Robert Hooke credit for the discovery of the Great Red Spot on
Jupiter (ca. 1665). Around 1690, Cassini was the first to observe differential
rotation within Jupiter's atmosphere.




http://antwrp.gsfc.nasa.gov/apod/

[Ptah]

1. hmmmm. Edited with correct link.

http://antwrp.gsfc.nasa.gov/apod/ap100215.html

[nytemare]

2. Huygens!

http://en.wikipedia.org/wiki/Christiaan_Huygens

:D

[Lionel Mandrake]

3. About Cassini and Astrology ...

Cassini's early interest and later disillusionment with astrology is a mirror of European society during his lifetime.

In the early 17th century, astrology was taken seriously by nobles and royalty and was taught in the universities. Astronomy was thought of mainly as an aid to astrology. In order to cast horoscopes, the astrologers had to know where the planets would be in the sky. There was a demand for accurate tables (known as ephemerides) that supplied this information. To compute such tables, astronomers used mathematical models of planetary orbits. The best model in Cassini's time was the one published by Kepler in 1609, which involved ellipses rather than circles.

During the course of the 17th century, astrology became more and more disreputable. Astronomy became disentangled from astrology, and astronomers became less likely to practice astrology. Cassini's loss of interest in astrology is not surprising under these circumstances.

Cassini's younger contemporary Isaac Newton (1642-1727) never showed the slightest interest in astrology.