Saturn's icy, impact-riddled moon Mimas slips briefly in front of Saturn's
moon Janus in this movie from Cassini. Mimas is 397 kilometers (247 miles)
across, while Janus is 181 kilometers (113 miles) across.
The movie was created from 37 original images taken over the course of 20
minutes as the spacecraft's narrow-angle camera remained pointed toward
Janus. Although Mimas moves a greater distance across the field of view,
Janus also moved perceptibly during this time. The images were aligned to
keep Janus close to the center of the scene. Additional frames were
inserted between the 37 Cassini images in order to smooth the appearance
of Mimas' movement--a scheme called interpolation. Close-up images from
the few minutes surrounding the occultation are arranged into a strip
along the bottom of the movie.
The terrain on Mimas seen here is about 80 degrees west of the terrain
seen in a previously released movie (see PIA06198), which showed the little
moon appearing to cross Saturn's ring plane from Cassini's vantage point.
In that previous movie, the rim of the large impact crater Herschel (130
kilometers, or 80 miles wide) was visible as a flattening of the moon's
eastern limb. In the new movie, Herschel is almost at dead center.
Contrast on Janus was mildly enhanced to aid the visibility of its
surface. The right side of Mimas appears bright because the moon was
partly overexposed in this image sequence.
The images for this movie were taken in visible light on March 5, 2005,
when Cassini was approximately 1.8 million kilometers (1.1 million miles)
from Mimas and 1.9 million kilometers (1.2 million miles) from Janus. The
image scale is approximately 11 kilometers (7 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages the
mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter and its two onboard cameras were designed, developed and
assembled at JPL. The imaging team is based at the Space Science
Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission, visit
http://saturn.jpl.nasa.gov and the Cassini imaging team home page,
http://ciclops.org.
