ASTROMETRICAL OBSERVATIONS OF THE EIGHT PRINCIPAL SATURN SATELLITES

The eight principal Saturn satellites, whose characteristics are given below, have a movement difficult to model because of the presence close to Saturn, flattened and because of their mutual perturbations, as in the case of the Galileans satellites. In order to adjust the dynamic models, many observations are necessary and must be realized very regularly. Some observations were carried out using the telescope of 120 cm. The field of 12 X 12 minutes of degree allows a reduction in equatorial co-ordinates J2000 thanks to the use of dense star catalogues like the USN0 A2. Examples of images obtained at the OHP are presented below.

Satellite:Magnit.1/2 GA
1000 km
Excent.Inclin.en ° sur l´équat.
de la planète
Période jDécouverte
Mimas I 12.9 185.54 0.019 05 1.56 0.942 422 Herschel (1789)
EnceladeII 11.7238.200.00490.031.370 218Herschel (1789)
TéthysIII10.3294.9920.01.101.887 803Cassini (1684)
DionéIV10.4377.6540.00220.012.736 916Cassini (1684)
RhéaV9.7527.3670.00030.354.517 503Cassini (1672)
Titan VI8.31 221.8030.02910.3015.945 446Huygens (1655)
HypérionVII14.21 481.10.10350.6421.276 673 Bond/Lassel (1848)
JapetVIII10.2/11.93 561.850.028318.579.330 954Cassini (1671)

Image of the Saturn satellites S-3, S-4, S-5, S-6, S-7 on a same image. The simultaneous visualization of these satellites and stars of the field is made difficult by the strong brightness of Saturn. Magnitude of S-3: 10.3, of S-4: 10.4, of S-5: 9.7, of S-6: 8.3 and of S-7: 14.2 Exposure time 20 sec, in R filter


S-3, S-4, S-5, S-6, S-7

Observations of the satellites Saturn phenomena were carried out using the telescope of 80 cm equipped with a CCD rapid functioning in two-dimensional photometric mode. These observations were carried out within as a part of international campaigns.

One will find below software providing other physical parameters and characteristic of these bodies and their ephemerides

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