PIA10443: Against a Hail of Stars

Against a Hail of Stars


Tethys appears here, against a background of star trails, in a view acquired as the icy moon exited Saturn's shadow. Tethys is illuminated in this view by two main sources: reflected "ringshine" and refracted sunlight passing through the edge of Saturn's atmosphere.

An observer viewing Saturn from the moon's surface would see the planet's southern hemisphere aglow with dimly reflected sunlight bouncing off the rings, called ringshine. They would also witness the beginning of an orbital sunrise.

The Cassini spacecraft shared a similar perspective when it acquired the images for PIA08329 (the principal difference being that Tethys is nearly in the ringplane and Cassini was 15 degrees above the ringplane when it acquired the images for the color mosaic.)

A long exposure time was required in order to image Tethys while it was in shadow, resulting in the stars' normally point-like images being smeared into streaks.

The view looks toward the northern hemisphere of Tethys (1,062 kilometers, or 660 miles across) from 36 degrees above the moon's equator. The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 30, 2008. The view was acquired at a distance of approximately 263,000 kilometers (163,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 52 degrees. Image scale is 16 kilometers (10 miles) per pixel.

Background Info:

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 operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/ . The Cassini imaging team homepage is at http://ciclops.org .

Cataloging Keywords:

Name Value Additional Values
Target Tethys Saturn
System Saturn
Target Type Satellite Planet
Mission Cassini-Huygens
Instrument Host Cassini Orbiter
Host Type Orbiter
Instrument Imaging Science Subsystem (ISS)
Detector Wide Angle Camera
Extra Keywords Atmosphere, Grayscale, Shadow, Visual
Acquisition Date
Release Date 2008-08-08
Date in Caption 2008-06-30
Image Credit NASA/JPL/Space Science Institute
Source photojournal.jpl.nasa.gov/catalog/PIA10443
Identifier PIA10443