OBJECT = COLUMN NAME = SEQ_COUNTER COLUMN_NUMBER = 1 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 1 DESCRIPTION = "CCSDS packet sequence counter." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SC_TIME COLUMN_NUMBER = 2 BYTES = 4 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 3 DESCRIPTION = "Spacecraft time in integer seconds that is transmitted to MESSENGER subsystems by the Integrated Electronics Module. This is assigned to the first spectral observation contained in a science packet. All spectra contained in the science packet will be associated with this start time. Unit is in Mission Elapsed Time which is the number of seconds since launch." END_OBJECT = COLUMN OBJECT = COLUMN NAME = PACKET_SUBSECONDS COLUMN_NUMBER = 3 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 7 DESCRIPTION = "Subsecond time in milliseconds that the telemetry packet was initiated. All spectra contained in the science packet will be associated with this subsecond start time. Unit is 5 milliseconds." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPACECRAFT_POSITION_VECTOR COLUMN_NUMBER = 4 BYTES = 12 DATA_TYPE = IEEE_REAL START_BYTE = 9 ITEMS = 3 ITEM_BYTES = 4 DESCRIPTION = "Derived vector in x,y,z giving spacecraft position in J2000 reference frame. Reference time will be SC_TIME plus PACKET_SUBSECONDS plus PERIOD * SPECTRUM_NUMBER." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SUN_POSITION_VECTOR COLUMN_NUMBER = 5 BYTES = 12 DATA_TYPE = IEEE_REAL START_BYTE = 21 ITEMS = 3 ITEM_BYTES = 4 DESCRIPTION = "Derived vector in x,y,z giving sun position in J2000 reference frame. Reference time will be SC_TIME plus PACKET_SUBSECONDS plus PERIOD * SPECTRUM_NUMBER." END_OBJECT = COLUMN OBJECT = COLUMN NAME = TARGET_LATITUDE COLUMN_NUMBER = 6 BYTES = 4 DATA_TYPE = IEEE_REAL START_BYTE = 33 DESCRIPTION = "Derived latitude on Mercury corresponding to spectral observation. Reference time will be SC_TIME plus PACKET_SUBSECONDS plus PERIOD * SPECTRUM_NUMBER." END_OBJECT = COLUMN OBJECT = COLUMN NAME = TARGET_LONGITUDE COLUMN_NUMBER = 7 BYTES = 4 DATA_TYPE = IEEE_REAL START_BYTE = 37 DESCRIPTION = "Derived longitude on Mercury corresponding to spectral observation. Reference time will be SC_TIME plus PACKET_SUBSECONDS plus PERIOD * SPECTRUM_NUMBER." END_OBJECT = COLUMN OBJECT = COLUMN NAME = INT_TIME COLUMN_NUMBER = 8 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 41 DESCRIPTION = "Amount of time the array detectors will integrate photon counts. Unit is 50 milliseconds." END_OBJECT = COLUMN OBJECT = COLUMN NAME = INT_COUNT COLUMN_NUMBER = 9 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 43 DESCRIPTION = "Total amount of integrations that will be taken." END_OBJECT = COLUMN OBJECT = COLUMN NAME = PERIOD COLUMN_NUMBER = 10 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 45 DESCRIPTION = "Interval time after which another integration will be started. Integrations are started at the top of every period. Time between integrations = PERIOD - INT_TIME. Unit is 0.05 second." END_OBJECT = COLUMN OBJECT = COLUMN NAME = DARK_FREQ COLUMN_NUMBER = 11 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 47 DESCRIPTION = "Dark counts will be collected every X integrations during a VIRS observation." END_OBJECT = COLUMN OBJECT = COLUMN NAME = TEMP_1 COLUMN_NUMBER = 12 BYTES = 4 DATA_TYPE = IEEE_REAL START_BYTE = 49 DESCRIPTION = "One of a redundant pair of array temperature sensors. A more complete description of this field can be found in the MASCS User's Guide. Conversion from raw counts (DN) to degrees Celsuis is: TEMP_1 = -3.34338E-18 * DN^5 + 8.979E-15 * DN^4 + 3.8131E-11 * DN^3 - 2.703E-8 * DN^2 - 0.0061 * DN - 1.67826 " END_OBJECT = COLUMN OBJECT = COLUMN NAME = TEMP_2 COLUMN_NUMBER = 13 BYTES = 4 DATA_TYPE = IEEE_REAL START_BYTE = 53 DESCRIPTION = "One of a redundant pair of array temperature sensors. A more complete description of this field can be found in the MASCS User's Guide.Conversion from raw counts (DN) to degrees Celsius is: For the VIS detector it is the same as for TEMP_1 For the NIR detector it is: TEMP_2 = -8.89100589E-18 * DN^5 - 9.72043502E-15 * DN^4 + 1.73862825E-10 * DN^3 + 3.39958815E-7 * DN^2 - 0.00702301101 * DN - 22.2879012 " END_OBJECT = COLUMN OBJECT = COLUMN NAME = NIR_GAIN COLUMN_NUMBER = 14 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 57 DESCRIPTION = "Gain of NIR array detector. A more complete description of this field can be found in the MASCS User's Guide.0=Low, 1=High, 999= N/A value when VIS dector is enabled. " END_OBJECT = COLUMN OBJECT = COLUMN NAME = OTHER_CHANNEL_ON COLUMN_NUMBER = 15 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 59 DESCRIPTION = "The other array is powered on or off (VIS in a NIR packet, NIR in a VIS packet. A value of 0 is off, a value of 1 is on." END_OBJECT = COLUMN OBJECT = COLUMN NAME = NIR_LAMP_ON COLUMN_NUMBER = 16 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 61 DESCRIPTION = "NIR flat field lamp is powered on or off. A value of 0 is off, a value of 1 is on." END_OBJECT = COLUMN OBJECT = COLUMN NAME = VIS_LAMP_ON COLUMN_NUMBER = 17 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 63 DESCRIPTION = "VIS flat field lamp is powered on or off. A value of 0 is off, a value of 1 is on." END_OBJECT = COLUMN OBJECT = COLUMN NAME = BINNING COLUMN_NUMBER = 18 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 65 DESCRIPTION = "Number of pixels that were binned together in the data." END_OBJECT = COLUMN OBJECT = COLUMN NAME = START_PIXEL COLUMN_NUMBER = 19 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 67 DESCRIPTION = "Start pixel of data captured by the detector array. For VIS the value can be from 0-511. For NIR the value can be from 0-255." END_OBJECT = COLUMN OBJECT = COLUMN NAME = END_PIXEL COLUMN_NUMBER = 20 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 69 DESCRIPTION = "End pixel of data captured by the detector array. For VIS the value can be from 0-511. For NIR the value can be from 0-255. The END_PIXEL must be greater than START_PIXEL." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPECTRUM_NUMBER COLUMN_NUMBER = 21 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 71 DESCRIPTION = "Ordered number sequence for spectra in a given observation. First spectrum is 0, second is 1, third is 2, and so on. Note that for observations which span multiple science packets, the numbering sequence is continuous." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPECTRUM_MET COLUMN_NUMBER = 22 BYTES = 4 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 73 DESCRIPTION = "A calculated value intended to reflect mission elapsed time since launch (seconds) at the start of an individual VIRS spectrum. This is derived using the following formula: SPECTRUM_MET = SC_TIME + floor(SPECTRUM_NUMBER*PERIOD*0.050) " END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPECTRUM_SUBSECONDS COLUMN_NUMBER = 23 BYTES = 2 DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 77 DESCRIPTION = " The calculated subsecond time in milliseconds that a VIRS integration was started. For each VIRS integration, SPECTRUM_MET plus SPECTRUM_SUBSECONDS gives the spacecraft time of the start of that integration. This is derived using the following formula: SPECTRUM_SUBSECONDS = (PACKET_SUBSECONDS + SPECTRUM_NUMBER * PERIOD * 50) mod 1000 " END_OBJECT = COLUMN OBJECT = COLUMN NAME = SPECTRUM_DATA COLUMN_NUMBER = 24 BYTES = 1024 DATA_TYPE = MSB_INTEGER START_BYTE = 79 ITEMS = 512 ITEM_BYTES = 2 DESCRIPTION = "The uncompressed spectrum at full 16-bit resolution. Data are zero-padded at the end if necessary to a total of 1024 bytes." END_OBJECT = COLUMN