TIMELINE
Prehistory
Humans make first
observations of the skies.
~800 BC
Assyrian and Babylonian astronomical observations are recorded.
~650 BC
Earliest known recorded observations
of Saturn are made in Mesopotamia.
~300 BC
Mythological view of Saturn as a god, by the Romans.
~150 AD
Hellenistic astronomer Claudius
Ptolemaeus (Ptolemy) makes observations of Saturn. From these, he makes
predictions of Saturn's future positions in sky.
700-800 AD
Islamic
astronomers working in Damascus and Baghdad observe and record Saturn's
position. They find that Ptolemy's predictions were wrong.
1610
Galileo notes the "triple planet" Saturn
with his telescope.
1612
Galileo observes Saturn
again. This time, it appears as a single golden-hued disc.
8
June 1625
Gian Domenico Cassini was born in Perinaldo, Italy.
14 Apr 1629
Christiaan Huygens was born into a
prominent Dutch family. He received the best education possible, including
training by Descartes.
1648
Cassini invited to work
at observatory of Marquis Cornelio Malvasia, near Bologna, where he worked till
going to France.
1650
Cassini was elected chair of
astronomy at the University of Bologna.
1651
Huygens published first work - Theoremata de quadratura hyperboles,
ellypsis et circuli - a geometrical work.
1653
Cassini designed and had constructed a new and larger meridian for the
church of San Petronio of Bologna. This helped to establish his reputation.
1655
Huygens visits Paris to make contacts with
lens makers. His successful aim for this trip was to improve the technique and
design of his own lenses.
March 1655
Huygens made
the discovers that would make him famous, including the discovery of Titan.
1656
Huygens published De Saturni luna
observation nova, to report his discoveries.
1656
Cassini published Specimen observationum Bononiensium qaue novissime in
D. Petronji templo ad astronomiae novae constitutionem haberi cepere.
1659
Cassini presented a planetary system model in
agreement with Tycho Brahe. Meanwhile, Huygens published Systema
Saturnia. It contained more observations of Saturn and its "arms". He
hypothesised that the "arms" were a ring surrounding the planet.
1663
Jean-Baptist Colbert recruited Huygens as a
founding member of the Academie Royale des Science.
July
1664
In his first discovery with a telescope, Cassini detected the
shadow of Jupiter's satellites and studied their revolutions. He was able to
calculate the period of Jupiter to be 9h 56m, only one minute off of the
currently accepted 9h 55m.
1667
Colbert offered
Cassini membership in the Academie Royale des Science as a regular
correspondent.
25 Feb 1669
Cassini departs for
Paris to aid in the establishment of an observatory. This was the end of his
life in Italy.
Sept 1671
Cassini discovered
Japetus, the second satellite of Saturn.
1672
Cassini discovered Rhea, the third satellite of Saturn.
1675
Cassini discovered the rings of Saturn by
observing a band of shadow on the planet's surface. He also discovered that the
ring was divided in two smaller rings by, what is now known as, "Cassini's
Division". He hypothesised that the rings were composed of a large number of
individual corpuscles, an idea that has been proven correct.
21
Mar 1684
Cassini observed two more satellites of Saturn - Tethys
and Dione.
1695
Huygens died in The Hague.
14 Sept 1712
Cassini died in Paris.
1789
Herschel discovers two satellites of
Saturn - Mimas and Enceladus. He also notes the thinness of the rings.
1848
Bond and Lassel discover the satellite
Hyperion.
1850
Bond, Bond and Daws discover inner
ring.
1857
Maxwell proves that the rings are not
solid.
1895
Keeler measures ring velocities.
1898
Pickering discovers satellite Phoebe.
1932
Wildt discovers methane and ammonia on Saturn.
1943-44
Kuiper discovers methane and ammonia on
Titan.
1979
Pioneer 11 flies past Saturn.
1980
Voyager 1 encounters Saturn.
1981
Voyager 2 encounters Saturn.
1989
Hubble Space Telescope's Wild Field and
Planetary Camera images Saturn for the first time.
1995
Hubble's Wide Field and Planetary Camera 2 images ring plane crossing.
1996-2000
Hubble images seen here were taken as the
ring goes for just past edge-on (bottom) to fully open (top) - see background
images.
1982
The formal beginning of
the Cassini-Huygens Space Mission was a Joint Working Group of the ESA and the
NAS. European scientist proposed a Saturn orbiter and Titan probe mission.
1983
US Solar System Exploration Committee
recommended NASA include a Titan probe and radar mapper in core program.
1984-85
Joint NASA/ESA assessment of Saturn probe
and Titan probe was completed.
1986
ESAs Science
Program Committee approved Cassini for Phase A study. Conditional start in 1987.
1987
Titan probe was renamed Huygens by ESA, as
part of Horizon 2000 space science program.
1987-88
NASA developing and designing Mariner Mark II spacecraft program.
Cassini-Huygens Mission was chosen as one of first missions within the Mariner
Mark II program.
1989
Funding for Cassini was
approved by the US Congress. NASA and ESA announced opportunity for scientists
to propose scientific investigations for the mission.
1992
Funding cap was placed on Mariner Mark II
program, that effectively ended the program. This also forced the Cassini
program to be restructed.
15 Oct 1997
Cassini-Huygens launched.
26 Apr 1998
Gravity
Assist past Venus at 284k (176 miles).
24 June 1999
Gravity Assist past Venus at 600k (370 miles).
18 Aug
1999
Gravity Assist past Earth at 1,171k (727 miles).
30 Dec 2000
Gravity Assist past Jupiter at
9,723,890k (6,042,145 miles).
1 July 2004
Cassini-Huygens arrived at Saturn.
26 Oct 2004
Cassini-Huygens passes Titan for first time at 1,200k (746 miles).
25 Dec 2004
Huygens probe is released from Cassini
spacecraft to begin a 21-day journey to the surface of Titan.
14
Jan 2005
Huygens probe descends to surface of Titan. Becomes first
man-made object to land on a planet in the outer solar system.
15 Feb 2005
Cassini spacecraft has first of six
encounters with Titain during year, they range in altitude from 1,025k (637
miles) to 60,000k (37,290 miles).
2006-2008
Cassini
spacecraft continues to orbit Saturn and studying the moons, mainly Titan, with
which it has 36 encounters during that time.
30 June2008
End of Prime Mission.
