CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Rev 101: Jan 19 - Jan 28 '09

Cassini continues its extended tour of Saturn on January 19 with Rev101, the spacecraft's 102nd orbit around the Ringed Planet.

Cassini begins Rev101 at its farthest distance from Saturn, called apoapse. At this point, Cassini is 1.18 million km (738,000 mi) from Saturn. The spacecraft is in a high-inclination orbit, providing an opportunity to study the rings and the polar regions of Saturn and its satellites. For the first four days of this revolution, ISS will focus on Saturn's atmosphere and small satellites. An astrometric observation, designed to improve our knowledge of the orbits of Saturn's small satellites, is planned for January 20. The moons to be imaged include: Prometheus, Pan, Epimetheus, Atlas, and Calypso. The Ultraviolet Imaging Spectrometer (UVIS) will map the aurorae in Saturn's north polar region on January 21 and 23. ISS, riding along during these UVIS observations, will focus on the hexagonal jet streams in the region. On January 22, UVIS and ISS will observe a stellar occultation by the B-type star, Beta Crucis (also known as Mimosa), of Saturn's upper atmosphere and C and D rings.

On January 23, Cassini reaches periapse, its closest point to Saturn on Rev101. At this point, Cassini will be 548,000 km (341,000 mi) from Saturn's center. Before periapse, ISS will acquire a four-hour photometry observation to measure the intensity of light coming from a crescent Mimas from a distance of 520,000 km (323,000 mi). The sequence will also allow ISS to observe part of the Saturn-facing hemisphere of that moon in Saturn-shine. The next day, the Visual and Infrared Mapping Spectrometer (VIMS) and ISS will image the southern hemisphere of a crescent Saturn. The VIMS team will use their 5-micron data to look at Saturn's cloud dynamics. At that near-infrared wavelength, VIMS can sense heat from the planet's interior which can be seen through gaps in the cloud decks, even as night darkens the hemisphere. Meanwhile, ISS will search for lightning and aurorae.

On January 25, ISS will image a crescent Titan from a distance of 1.62 million km (1 million mi), looking at the moon's upper haze layers and searching for clouds. ISS and VIMS will also observe the south polar region of Saturn, once again focusing on cloud dynamics in an area of waning sunlight as autumn approaches. On January 27, ISS and UVIS will again acquire an auroral observation of Saturn, this time looking near Saturn's south pole for aurorae. ISS also will take an astrometric sequence involving Atlas, Pandora, Telesto, Prometheus, and Anthe.

Cassini reaches apoapse on January 28, bringing Rev101 to an end. To close out the revolution, ISS will acquire another astrometric observation of Telesto, Prometheus, Pandora, Daphnis, and the outer satellite Loge (Saturn XLVI). ISS and UVIS will then observe Enceladus from a distance of 1.37 million km (851,000 mi). Finally, Cassini will turn its cameras to Titan, observing that large satellite's sub-Saturn hemisphere from a distance of 2.32 million km (1.44 million mi).

Image products created in Celestia. All dates in Coordinated Universal Time (UTC).