PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 FILE_RECORDS = 1329 ^SERIES = "PPSGEOM.TAB" DATA_SET_ID = "VG2-SR/UR/NR-PPS-2/4-OCC-V1.0" RING_OBSERVATION_ID = "S/OCC/VG2/PPS/1981-08-25/DELTA_SCO" PRODUCT_ID = "PPSGEOM.TAB" PRODUCT_TYPE = FOOTPRINT_GEOMETRY PRODUCT_CREATION_TIME = 2003-09-26T16:00:00 SOURCE_PRODUCT_ID = "PS1G02.TAB" SPACECRAFT_NAME = "VOYAGER 2" SPACECRAFT_ID = VG2 INSTRUMENT_NAME = "PHOTOPOLARIMETER SUBSYSTEM" INSTRUMENT_ID = PPS TARGET_NAME = "S RINGS" START_TIME = 1981-08-25T23:46:11.425 STOP_TIME = 1981-08-26T01:57:23.417 SPACECRAFT_CLOCK_START_COUNT = "44001:04:601" /*Voyager FDS count*/ SPACECRAFT_CLOCK_STOP_COUNT = "44003:50:601" /* Cataloging information */ RING_EVENT_START_TIME = 1981-08-25T23:46:10.471 RING_EVENT_STOP_TIME = 1981-08-26T01:58:58.831 MINIMUM_RING_RADIUS = 62544.53777 MAXIMUM_RING_RADIUS = 144556.43899 RING_OCCULTATION_DIRECTION = EGRESS INCIDENCE_ANGLE = 61.30638 /* Source information */ SOFTWARE_NAME = "RINGINT" SOFTWARE_VERSION_ID = "1.0" NAIF_DATA_SET_ID = 'N/A' COORDINATE_SYSTEM_ID = (J2000, B1950) STAR_NAME = "DELTA SCO" RIGHT_ASCENSION = (240.08457371, 239.3440704) DECLINATION = (-22.62171121, -22.4813078) FEATURE_NAME = "EQUATORIAL RING" REFERENCE_TIME = 1981-08-25T00:00:00 RING_INCLINATION = 0.0 RING_ASCENDING_NODE_LONGITUDE = 0.0 NODAL_REGRESSION_RATE = 0.0 POLE_RIGHT_ASCENSION = (40.589217, 38.4107) POLE_DECLINATION = (83.538364, 83.32352) OBJECT = SERIES NAME = OCCULTATION_GEOMETRY INTERCHANGE_FORMAT = ASCII ROWS = 1329 COLUMNS = 7 ROW_BYTES = 80 SAMPLING_PARAMETER_NAME = RECORD_INDEX SAMPLING_PARAMETER_UNIT = 'N/A' MINIMUM_SAMPLING_PARAMETER = -15.998333 MAXIMUM_SAMPLING_PARAMETER = 1312.001667 SAMPLING_PARAMETER_INTERVAL = 1.0 DESCRIPTION = "This is a sample geometry file for use with the PDS Rings Node Profile Library. It is based on file GEOMETRY/PS1G02.TAB from the Voyager PPS ring occultation data set, volume VG_2801. This is a table of geometry parameters associated with the Voyager 2 PPS egress occultation of delta Scorpii by Saturn's rings. Geometry parameters are given for the beginning of every PPS data record, where a record consists of 600 individual samples, each separated in time by 10 msec. Hence, each record consists of 6 seconds of data. This file describes the occultation footprint on the ring plane. This particular file is based on an occultation geometry reconstruction by Philip D. Nicholson. It is documented in Nicholson, P.D., M.L. Cooke, and E. Pelton 1990. An absolute radius scale for Saturn's rings. Astronomical Journal 100, 1339-1362. This file was generated by program DOCUMENT/GEOMETRY/PDN/RINGINT.FOR with these inputs: (1) Occultation options: Saturn - iota Her/delta Sco ....1 Uranus - sigma Sgr/beta Per ... 2 Neptune - sigma Sgr ........... 3 ... 1 Enter 1 for iota Her, 2 for delta Sco ingress, or 3 for delta Sco egress: 3 (2) Enter start and stop FDS counts (x,y,z): 44001 04 601 44003 50 601 (3) Enter FDS increment (z units = TV lines): 100 (4) Enter 1 to change default pole position: 0 (5) Enter PPS sample number for FDS tag (nominally 1): 1 The output file RINGINT.TAB was then renamed." OBJECT = COLUMN NAME = RECORD_INDEX DATA_TYPE = ASCII_INTEGER START_BYTE = 1 BYTES = 4 FORMAT = "I4" UNIT = 'N/A' OFFSET = 0.001667 DESCRIPTION = "Record index value. Each PPS data record consists of 600 samples, where the first record in the data file has index 0. Note that the geometry is actually tabulated for the second sample in each record; hence an offset value of 1/600 should be applied. The origin of this correction is discussed in Appendix A of Nicholson, P. D., M. L. Cooke, and E. Pelton 1990. An absolute radius scale for Saturn's rings. Astron. J. 100, 1339-1362." END_OBJECT = COLUMN OBJECT = COLUMN NAME = RING_INTERCEPT_TIME DATA_TYPE = ASCII_REAL START_BYTE = 6 BYTES = 11 FORMAT = "F11.5" UNIT = SECOND REFERENCE_TIME = 1981-08-25T00:00:00 DESCRIPTION = "Time at which the measured photons intercepted the ring plane, measured in seconds from 0:00:00 UTC on 25 August, 1981." END_OBJECT = COLUMN OBJECT = COLUMN NAME = RING_INTERCEPT_RADIUS DATA_TYPE = ASCII_REAL START_BYTE = 18 BYTES = 12 FORMAT = "F12.5" UNIT = KILOMETER DESCRIPTION = "Radial distance of the occultation intercept point from the center of of the planet, in kilometers. Distances are measured along the ring plane." END_OBJECT = COLUMN OBJECT = COLUMN NAME = RING_INTERCEPT_LONGITUDE DATA_TYPE = ASCII_REAL START_BYTE = 31 BYTES = 10 FORMAT = "F10.6" UNIT = DEGREE DESCRIPTION = "Inertial longitude of the intercept point in the ring plane, in degrees. By default, longitudes are measured from the ring plane ascending node on Earth's mean equator of J2000. The J2000 frame is the default for all PDS data sets. However, this geometry file was generated using B1950 coordinates. Methods for converting between the two frames are discussed in file DOCUMENT/GEOMETRY/POLES.TXT." END_OBJECT = COLUMN OBJECT = COLUMN NAME = B1950_RING_INTERCEPT_LONGITUDE DATA_TYPE = ASCII_REAL START_BYTE = 42 BYTES = 10 FORMAT = "F10.6" UNIT = DEGREE DESCRIPTION = "Inertial longitude of the intercept point in the ring plane, in degrees. B1950 longitudes are measured from the ring plane ascending node on Earth's mean equator of B1950. The J2000 frame is the default for all PDS data sets. However, this geometry file was generated using B1950 coordinates. Methods for converting between the two frames are discussed in file DOCUMENT/GEOMETRY/POLES.TXT." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPACECRAFT_EVENT_TIME DATA_TYPE = ASCII_REAL START_BYTE = 53 BYTES = 11 FORMAT = "F11.5" UNIT = SECOND REFERENCE_TIME = 1981-08-25T00:00:00 DESCRIPTION = "Time at which the measured photons were received by Voyager, measured in seconds from 0:00:00 UTC on 25 August, 1981." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPACECRAFT_CLOCK_COUNT DATA_TYPE = CHARACTER START_BYTE = 66 BYTES = 12 FORMAT = "A12" UNIT = 'N/A' DESCRIPTION = "Voyager FDS ('Flight Data System') count associated with the beginning of this data record. The field format is 'hhhhh:mm:sss', specifying the FDS 'hours', 'minutes' and 'seconds'. There are 60 FDS minutes (numbered 0-59) in an FDS hour. For the PPS instrument, there are 800 FDS seconds (numbered 1-800) in an FDS minute. An FDS hour equals 48 true minutes; an FDS minute equals 48 true seconds; an FDS second equals 0.06 true seconds. Each PPS record consists of 100 FDS seconds or 6 true seconds of data." END_OBJECT = COLUMN END_OBJECT = SERIES END