EXPLORE


JOINRENEWJOIN

Year in Space Calendar
  

Space Topics: Cassini-Huygens

Selected Data from Cassini's Cameras

Credit for these images belongs to NASA / JPL / Space Science Institute.

The images that we see of Saturn and its moons across the Internet are just a tiny fraction of the images that Cassini returns to Earth. The Cassini mission works hard to prepare and publish about one image a day; but the spacecraft typically acquires anywhere from a dozen to several hundred images each and every day of its mission. Beyond the few images that are sent out with press releases, NASA has always required missions to place all of their data into a public repository, the Planetary Data System (PDS), after a proprietary period.  However, the PDS is designed for researchers, so it can be confusing and difficult for the public to access. On these pages, The Planetary Society is attempting to make much more of Cassini's image data accessible to the public.

Links below will take you to a page for each of Saturn's icy moons.  Each page contains every Cassini ISS image of that moon from the PDS that was taken within a minimum distance, a different one for each moon, depending upon its diameter. Enjoy, and if you make any pretty pictures with these data, please email them to

JavaScript required to view email.

For information on basic image processing techniques, including how to compose color images, visit The Planetary Society's Space Imaging site. If you find these pages to be of value, please consider making a small donation to The Planetary Society. There is also a database containing all metadata for all of Cassini's images released to the PDS.

Update, April 10, 2008: The pages have been updated with images from the April 1, 2008 release of data to the Planetary Data System. New images were added for Dione, Enceladus, Mimas, Rhea, Tethys, Atlas, Epimetheus, Janus, and Prometheus. (Those links take you to the latest releases only; use the links below for the full catalogs from each moon.)

These pages were last updated in April 2008, and include images taken by Cassini through June 30, 2007.


Cassini's Observations

The images are organized into observations.  An "observation" is a coherent sequence of images taken in fairly rapid succession by the Cassini spacecraft.  An observation can consist of just one image, or it might consist of many images of the same moon captured through different filters, or it might consist of many "pointings" of the camera as the camera moves to gather tiles for an image mosaic.  Observations are named with codes that provide information about the observation, such as what orbit Cassini was on, what the target was, an abbreviation indicating the purpose of the observation (some examples: "OPNAV" for optical navigation images, "GLOCOL" for global color images, "LIMTOP" for images designed to observe topography across the moon's limb).

Here's an example observation:

ISS_016DI_GLOCOL001_PRIME
Starting at 10/11/2005 9:48:41 AM, Range 293410 km, Phase 21.9 deg, Sub-SC lat/lon -0.5 / 136
CL1-CL2 - CL1-UV3 - CL1-GRN - CL1-IR1 - CL1-IR3 - UV1-CL2 - BL1-CL2 - RED-CL2 - IR2-CL2 - IR4-CL2 - UV2-CL2 - UV2-UV3 - BL1-GRN - RED-GRN - RED-IR1 - IR2-IR1 - IR2-IR3 - IR4-IR3 - HAL-CL2 (LOSSY) - CL1-CB2 (LOSSY) - CL1-CB3 (LOSSY) - CL1-MT1 (LOSSY) - CL1-GRN (LOSSY) - P0-GRN - P60-GRN - P120-GRN - P0-UV3 - P60-UV3 - P120-UV3 - P0-MT2 - P60-MT2 - P120-MT2 - WAC CB2-IRP0 - WAC CB2-IRP90 - WAC IR4-IRP0 - WAC IR4-IRP90
Ending at 10/11/2005 10:07:26 AM, Range 280432 km, Phase 22 deg, Sub-SC lat/lon -0.5 / 137.5
This observation was taken on Cassini's Rev 16 orbit of Saturn ("016"), of Dione ("DI"), for the purpose of global color mapping ("GLOCOL001"), with ISS controlling the spacecraft pointing ("PRIME").  The observation took about 20 minutes to execute (from 9:48 to 10:26 on October 11, 2005), and took place while Cassini was about 290,000 kilometers from Dione; Cassini approached Dione throughout the observation, so successive images show Dione getting slightly larger in Cassini's field of view.  Dione is lit from a relatively high sun angle (phase 21.9 degrees), and Cassini's view was centered near Dione's equator at a longitude of about 136 degrees east.  The observation consists of a total of 36 images captured through many different combinations of filters; clicking on each filter pair will bring up the image captured through that pair of filters.  (Cassini's cameras have two filter wheels, so each image is taken through two filters in combination: for example, the CL1-GRN image was taken through clear and green filters.  Click here for more information about the Cassini camera and filters.)  Most of the images were taken through Cassini's narrow-angle camera, but some ("WAC") were taken through the wide-angle camera, which has 10 times the field of view but 1/10 the resolution of the narrow-angle camera.  Some of the images were compressed using a lossy compression scheme ("LOSSY") aboard the spacecraft before being returned to Earth.