Use OPUS to search for specific Cassini data products using a wide range of criteria including enhanced geometric metadata produced at the Rings node. The enhanced geometric metadata includes information appropriate to planet and satellite searches as well as enhanced ring geometry.
Supports CIRS (limited), ISS, UVIS, and VIMS.
Search results include data files, tables of associated metadata, and browse thumbnails for each image. User selected data files can be bundled as tar.gz files for easy downloading.
See section 4 below for additional hints on using OPUS.
The Access ISS Data tab, provides links for each data volume, including links to the volume, to tar.gz files of the volume, and links to directories containing “thumbnail” previews of the images on the volume.
You can use the VOLUME_ID coupled with the index files provided on the ISS volumes to help you find specific data (see below).
The volume ID takes the form COISS_Nxxx, where:
COISS is the PDS abbreviation for Cassini Orbiter, Imaging Science Subsytem
N is one of the following the mission phase identifiers:
xxx is the sequential volume number, begining with 001 for each of the three data sets.
Each volume has an index subdirectory containing three files:
Users are strongly encouraged to read an indxinfo.txt before working with the INDEX files.
NOTE that these files are large, typically, 12 Mbytes.
Columns in the index file that may be particularly useful to ring scientists include those for:
RINGS_FLAG, TARGET_NAME, TARGET_DISTANCE, MAXIMUM_RING_RADIUS, MINIMUM_RING_RADIUS, RING_CENTER_LATITUDE, RING_CENTER_LONGITUDE, RING_EMISSION_ANGLE, RING_INCIDENCE_ANGLE, and OBSERVATION_ID
The OBSERVATION_ID is a string constructed from the instrument ID, the orbit number, the target code, a description of the observation, and instance number. For example, VIMS_000RI_RINGMOS103_PRIME is some of the data taken by VIMS during orbit 000 to produce a radial mosaic of the rings.
“Observation Name” under “Cassin Mission Constraints” allows you to search in OPUS on the Cassini observation ID, or sub-strings within the observation ID. In OPUS, first select either the mission or instrument host = cassini, or instrument name = any of the Cassini instruments. Either action will expose the Cassini mission constraints.
Searching OPUS or the index file for the substring RI_ will identify general ring observations. Observations devoted to a specific ring (A through G) may be indicated by RA_, RB_, RC, RD_, RE_, RF_, and RG_ respectively