Data Set Information
DATA_SET_NAME GIOTTO EXTENDED MISSION, OPE, V1.0
DATA_SET_ID GIO-C-OPE-3-RDR-GRIGG-SKJELL-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : This dataset includes raw and calibrated results from the Optical Probe Experiment (OPE) aboard the Giotto spacecraft during its extended mission to comet 26P/Grigg-Skjellerup, as well as the data used in the calibration. Description of the instrument by A. C. Levasseur-Regourd: 'The OPE polarimeter was designed to measure the polarized components of the light in seven bandpasses or channels, ranging from the near ultraviolet to the near infrared. Three channels (so- called blue, green and red) were devoted to the observation of the scattering of solar light by cometary dust grains, in emission-free countinuum bands. Four other channels (so called OH, CN, CO+, C2) were devoted to the observation of light emitted by cometary gases. 'The imaging of a mosaic of interference filters (placed in front of the objective lens and organized into a mosaic to compensate for the chromatic effects) onto a microchannel plate allowed the spectral discrimination to be achieved. A polaroid analyzer, placed in front of each filter, except the CO+ one, allowed the polarization to be determined by the rotation of the analyzer with the spin of the spacecraft. During a spin period (of approximately 4 seconds), eight consecutive measurements of the polarized intensity, Ii, Ii+1, Ii+2, etc, (of approximately half a second each), were performed in the seven channels at eight so-called clock angles.' Parameters : The principal parameter in each dataset is counts in each channel. The raw data file contains a time-ordered list of counts in all instrument channels. Two separate files provide calibrated results in two of the bands (blue and green continuum), listed with respect to distance along the track of the spacecraft. This distance has its zero point at the nominal time of closest approach near 15:30:45. Data : There are four separate data files: operaw Raw, decommuted counts in chronological order opeblue Calibrated counts as a function of distance, blue continuum opegreen Calibrated counts as a function of distance, green continuum opecal Calibration data for both blue and green filters
DATA_SET_RELEASE_DATE 1995-12-31T00:00:00.000Z
START_TIME 1992-07-10T02:16:39.071Z
STOP_TIME 1992-07-10T04:14:59.287Z
MISSION_NAME GIOTTO EXTENDED MISSION
MISSION_START_DATE 1990-01-01T12:00:00.000Z
MISSION_STOP_DATE 1992-01-01T12:00:00.000Z
TARGET_NAME 26P/GRIGG-SKJELLERUP 1 (1922 K1)
TARGET_TYPE COMET
INSTRUMENT_HOST_ID GIO
INSTRUMENT_NAME OPTICAL PROBE EXPERIMENT
INSTRUMENT_ID OPE
INSTRUMENT_TYPE PHOTOPOLARIMETER
NODE_NAME Small Bodies
ARCHIVE_STATUS SAFED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : See the accopmanying documentation (opechan.doc) file for a discussion of the sensitivity and residual effects on the OPE instrument from the preceding encounter with comet 1P/Halley. Review : This data set never underwent formal PDS review.
CITATION_DESCRIPTION Unknown
ABSTRACT_TEXT This dataset includes raw and calibrated results from the Optical Probe Experiment (OPE) aboard the Giotto spacecraft during its extended mission to comet 26P/Grigg-Skjellerup, as well as the data used in the calibration.
PRODUCER_FULL_NAME PDS SMALL BODIES NODE
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