PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM ^TABLE = "WAGO.TAB" DATA_SET_ID = "MGS-M-MOC-NA/WA-2-SDP-L0-V1.0" SPACECRAFT_NAME = "MARS GLOBAL SURVEYOR" INSTRUMENT_NAME = "MARS ORBITER CAMERA" TARGET_NAME = MARS MISSION_PHASE_NAME = "MAPPING" OBJECT = TABLE INTERCHANGE_FORMAT = ASCII ROWS = 3125 COLUMNS = 04 ROW_BYTES = 37 DESCRIPTION = "Beginning in mapping subphase M00, the gain and offset for the WA cameras were changed periodically over the orbit to optimize the images for dynamic range and avoid saturation. Beginning in subphase M01, this was done systematically over the orbit to account for lighting geometry effects. As a result, many of the longer-duration WA images actually span multiple gain-offset states, although their labels and ancillary table entries only contain the state in effect at the beginning of data acquisition. These changes are visible in the images as brightness discontinuities. For some applications, it is useful to know the time of the gain-offset state changes so that calibration can account for them. This table gives this information. As the timing knowledge of the gain-offset changes is only accurate to 1/8 of a second, and the WA line rate is somewhat faster than this and not an even multiple of 1/8 second, the line on which the brightness discontinuity occurs may not match precisely the line computed from the image start time, line rate, and known time of state change. In addition, changes in highly-summed images (such as global map swaths) may result in summed output lines having been created in the instrument from unsummed input lines taken in different states. Some form of ad hoc brightness matching algorithm may be useful in these cases." OBJECT = COLUMN NAME = FILTER_NAME COLUMN_NUMBER = 1 DATA_TYPE = CHARACTER START_BYTE = 2 BYTES = 4 FORMAT = "A4" DESCRIPTION = "filter name (RED or BLUE, N/A for NA)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPACECRAFT_CLOCK_START_COUNT COLUMN_NUMBER = 2 DATA_TYPE = CHARACTER START_BYTE = 9 BYTES = 15 FORMAT = "A15" DESCRIPTION = "spacecraft clock value at gain state change" END_OBJECT = COLUMN OBJECT = COLUMN NAME = GAIN_MODE_ID COLUMN_NUMBER = 3 DATA_TYPE = CHARACTER START_BYTE = 27 BYTES = 2 FORMAT = "A2" DESCRIPTION = "gain mode (see documentation)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = OFFSET_MODE_ID COLUMN_NUMBER = 4 DATA_TYPE = CHARACTER START_BYTE = 32 BYTES = 3 FORMAT = "A3" DESCRIPTION = "offset mode (see documentation)" END_OBJECT = COLUMN END_OBJECT = TABLE END