/*** ALL VALUES TAKEN DIRECTLY FROM UVVS HEADER CDR ***/ OBJECT = COLUMN NAME = SC_TIME COLUMN_NUMBER = 1 BYTES = 4 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 1 DESCRIPTION = "Spacecraft time in integer seconds that is transmitted to the MESSENGER subsystems by the Integrated Electronics Module. This is assigned as the start time of the UVVS observation. A UVVS observation is defined as all the scan data contained within one UVVS science packet. This is due to the highly configurable nature of the instrument, i.e. it can be commanded to take multiple scans over multiple wavelengths. Unit is in mission elapsed time which is the number of seconds since launch. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = PACKET_SUBSECONDS COLUMN_NUMBER = 2 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 5 DESCRIPTION = "The subsecond time in milliseconds that the telemetry packet was initiated. SC_TIME plus PACKET_SUBSECONDS is the spacecraft time of the first integration. Values of this field are in units of 5 milliseconds. For example, a value of 10 refers to a time of 50 milliseconds. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = START_POS COLUMN_NUMBER = 3 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 7 DESCRIPTION = "Start position where grating drive begins a scan. Grating drive step position corresponds to a given wavelength being observed by an instrument. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = STEP_COUNT COLUMN_NUMBER = 4 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 9 DESCRIPTION = "Number of steps the grating drive will take in a scan. This directly corresponds to the range of wavelengths that will be observed in one UVVS observation. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = INT_TIME COLUMN_NUMBER = 5 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 11 DESCRIPTION = "Integration time in grating drive loop control interrupt periods (nominally 3000 Hz). For example, the actual integration time in seconds is INT_TIME/3000. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = STEP_TIME COLUMN_NUMBER = 6 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 13 DESCRIPTION = "Step time in grating drive loop control interrupt periods (nominally 3000 Hz). For example, the actual step time in seconds is STEP_TIME/3000. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = PHASE_OFFSET COLUMN_NUMBER = 7 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 15 DESCRIPTION = "Phase offset in grating drive loop control interrupt periods. Phase offset between the beginning of grating drive step and the start of a PMT integration in units of 0.3 milliseconds. Default value is 0 (no phase offset). By setting the phase offset to a non-zero value (reserved for contingency operations), the user will tell the software to initiate a step before the end of an integration, accounting for latencies in the motor controller. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SCAN_CYCLES COLUMN_NUMBER = 8 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 17 DESCRIPTION = "Number of times to repeat scan. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = ZIGZAG COLUMN_NUMBER = 9 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 19 DESCRIPTION = "Indicates whether grating drive moves in a 'triangle' (stepping up, then stepping down), or 'sawtooth' (stepping up, then 'flying' down) motion. A 'triangle' observation takes one grating scan stepping up the grating, then reverses direction and takes the next grating scan stepping back down the grating. A 'sawtooth' observation takes one grating scan stepping up the grating, then 'flies' the grating back to the START_POSITION to take the next observation. =0 disable, =1 enable. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = COMPRESSION COLUMN_NUMBER = 10 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 21 DESCRIPTION = "Selectable data size, =0 16 bit data, =1 9 bit data. Used to help determine the total number of data points contained in the observation. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SLIT_MASK_POS COLUMN_NUMBER = 11 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 23 DESCRIPTION = "Indicates whether slit mask is in atmospheric (open) or surface (closed) position. Atmospheric slit results in a 1 deg. by 0.04 deg. instantaneous field of view (iFOV). Surface slit results in a 0.05 deg. by 0.04 deg. iFOV. =0 closed, =1 open. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = GD_SETTLE_CTR COLUMN_NUMBER = 12 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 25 DESCRIPTION = "Number of times during integration that the grating drive wandered outside target range. This can happen very rarely with an encoder misread, or motor misstep, and would result in an offset of step-number to wavelength correlations for subsequent observations in a given scan. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = NUM_SCAN_VALUES COLUMN_NUMBER = 13 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 27 DESCRIPTION = "Total number of values or data points in the entire scan observation. Used to determine the number of valid data points in the SCAN_DATA column. Maximum value is 3626. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = STEP_SIZE COLUMN_NUMBER = 14 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 29 DESCRIPTION = "Step size in arcmin units. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = COADD COLUMN_NUMBER = 15 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 31 DESCRIPTION = "Number of steps coadded to make a single observation. Default = 1, i.e. one step per observation. PER OBSERVATION column." END_OBJECT = COLUMN OBJECT = COLUMN NAME = CALIBRATION_SOFTWARE_VERSION COLUMN_NUMBER = 16 BYTES = 4 DATA_TYPE = IEEE_REAL START_BYTE = 33 DESCRIPTION = "Indicates version of calibration software used to generate UVVS Surface Reflectance Science DDR. Increments with reprocessing of DDRs. PER OBSERVATION column." END_OBJECT = COLUMN