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CASSINI PHOTOGRAPHER

Daphnis close up

Saturn small moon poses for Cassini lens. It is closest picture of the small moon that orbits within the Keeler Gap obtained yet

The wavemaker moon, Daphnis, is featured in this view, taken as Cassini spacecraft made one of its ring-grazing passes over the outer edges of Saturn's rings on 16 January 2017. This is the closest view of the small moon obtained yet.  

Daphnis (8 kilometers across) orbits within the 42-kilometer wide Keeler Gap. Cassini's viewing angle causes the gap to appear narrower than it actually is, due to foreshortening.  

The little moon's gravity raises waves in the edges of the gap in both the horizontal and vertical directions. Cassini was able to observe the vertical structures in 2009, around the time of Saturn's equinox.  

Like a couple of Saturn's other small ring moons, Atlas and Pan, Daphnis appears to have a narrow ridge around its equator and a fairly smooth mantle of material on its surface, likely an accumulation of fine particles from the rings. A few craters are obvious at this resolution. An additional ridge can be seen further north that runs parallel to the equatorial band.  

Fine details in the rings are also on display in this image. In particular, a grainy texture is seen in several wide lanes which hints at structures where particles are clumping together. In comparison to the otherwise sharp edges of the Keeler Gap, the wave peak in the gap edge at left has a softened appearance. This is possibly due to the movement of fine ring particles being spread out into the gap following Daphnis' last close approach to that edge on a previous orbit. 

A faint, narrow tendril of ring material follows just behind Daphnis (to its left). This may have resulted from a moment when Daphnis drew a packet of material out of the ring, and now that packet is spreading itself out. 

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 28,000 kilometers from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 71 degrees.  

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space AgencyASI is one of the partners of the Cassini mission: on the basis of a cooperation agreement with NASA it has developed for Cassini the high gain antenna with the incorporation of a low-gain antenna (that ensure telecommunications with the Earth for the entire duration of the mission), the VIMS spectrometer, the radio-science subsystem (RSIS) and the radar which also uses the high-gain antenna. ASI has also developed for the Huygens spacecraft the HASI instrument which measured the physical properties of the atmosphere and Titan's surface.