Why are sections of Cassini photographs blurred?

Question

In this photograph of Rhea, taken by the Cassini orbiter, there are sections near the terminator that are very blurred, a stark contrast from the crisp sharpness of the rest of the image. The blurred sections look polygonal in shape, with defined edges.

^{Return to Rhea (PIA19057). Zoomed in to the terminator, blurred portion highlighted. Courtesy NASA JPL.}

Why are these portions blurred? My theory is that Cassini could not take photographs of those regions with its narrow-field camera, and hence used wide-field data instead. Am I right?

Answer 1

Your guess is correct. To quote NASA's page,

The mosaics each consist of multiple narrow-angle camera (NAC) images with data from the wide-angle camera used to fill in areas where NAC data was not available.

Answer 2

Yes, these are composites of WAC and NAC images. The camera operation planners do their best to cover a target sufficient for good science, but sometimes time or data volume constraints prevent catching every part of an object.

The image caption on the CICLOPS site says "The mosaics each consist of multiple narrow-angle camera (NAC) images with data from the wide-angle camera used to fill in areas where NAC data was not available."