CCSD3ZF0000100000001NJPL3IF0PDSX00000001 PDS_VERSION_ID = PDS3 /* File Format and Length */ RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 30 FILE_RECORDS = 1134760 DATA_SET_ID = "IRAS-D-FPA-3-RDR-ZOHF-LOW-RES-V1.0" DATA_SET_NAME = "IRAS LOW RESOLUTION ZODIACAL HISTORY FILE V1.0" OBJECT = TABLE ROWS = 1134760 ROW_BYTES = 30 INTERCHANGE_FORMAT = BINARY COLUMNS = 8 ^STRUCTURE = "ZOHF1.DAT" DESCRIPTION = "The IRAS Low-Resolution (0.5 degree) Zodiacal Observational History File consists of the time-ordered IRAS survey data averaged into 1/2 X 1/2 degree square pixels along with pointing and timing information, covering the entire mission. These pixels contain the average of all detector samples in a given wavelength band summed over a time corresponding to a 1/2 degree scan. The data used in generating this file (Version 3) is not identical to that used in generating the 2' X 1/2 degree ZOHF (Version 2). An explanation of the differences in calibration between the two datasets and a statistical analysis of the differences in the resultant positions and fluxes may be found in Oken et al. (1988) and Boulanger (1988). General information about the Infrared Astronomical Satellite (IRAS) and its mission may be found in Beichman et al. (1989) and Neugebauer et al. (1984). " NOTE = " While generally characterized as being 1/2 x 1/2 degree pixels, the actual pixel dimensions (in arc-minutes) are as follows: Band Wavelength In-Scan Cross-Scan 1 12 30.8 28.4 2 25 30.8 30.3 3 60 30.8 28.5 4 100 30.8 30.5 (Oken et al. 1988)." See /INDEX/ZOHF_LOW.TAB for references to the pointing information for the observations contained within this binary file." OBJECT = COLUMN NAME = SAMPLE_TIME UNIT = SECOND DESCRIPTION = " The time associated with a given pixel corresponds to the sample time of the first (100 micron) detector averaged into that pixel measured in seconds since 0 hours Universal Time Coordinated, 1 January 1981 (Beichman et al. 1988). Time values may be off by as much as two seconds." NOTE = "The elapsed time does NOT correspond to the time at which the satellite boresight crosses the given pixel location." DATA_TYPE = REAL FORMAT = "F11.2" START_BYTE = 1 BYTES = 8 END_OBJECT OBJECT = COLUMN NAME = INCLINATION_OBSERVATION UNIT = CENTIDEGREES DESCRIPTION = "The angle (INCL) between the ecliptic plane and the plane containing the Earth, Sun, and observation direction (i.e., the azimuth angle about the Earth-Sun axis) (Beichman et al. 1989). INCL is zero as the satellite looks at the ecliptic plane in the direction opposite to the motion of the Earth around the Sun. It increases clockwise along the Earth-Sun axis, facing the Sun - opposite from the direction of motion of the satellite in its orbit about the Earth. In units of degrees, INCL is related to clock angle (CL) by the relation INCL=90-CL. INCL also is related to geocentric ecliptic latitude (BETA) through the relation SIN(BETA)=SIN(INCL)SIN(SE), where SE is the solar elongation of observation." DATA_TYPE = INTEGER START_BYTE = 9 BYTES = 2 END_OBJECT OBJECT = COLUMN NAME = BETA UNIT = CENTIDEGREES DESCRIPTION = "The geocentric ecliptic latitude (Equinox 1950.0, Epoch 1983.5) of observation." DATA_TYPE = INTEGER START_BYTE = 11 BYTES = 2 END_OBJECT OBJECT = COLUMN NAME = LAMBDA UNIT = CENTIDEGREES DESCRIPTION = "The geocentric ecliptic longitude (Equinox 1950.0, Epoch 1983.5) of observation. This is related to the solar elongation of observation (SE) and geocentric ecliptic latitude and the geocentric ecliptic longitude of the sun (LSUN) through the relation COS(SE)=COS(BETA)COS(LAMBDA-LSUN)." DATA_TYPE = INTEGER START_BYTE = 13 BYTES = 2 END_OBJECT OBJECT = COLUMN NAME = FLUX_12 UNIT = "JANSKY PER STERADIAN" DESCRIPTION = "Flux densities (1 Jy = 1.e-26 Watt/ (meter*2)Hz) are calculated from inband flux (Watts/meter^2) assuming the external source function to be proportional to 1/frequency. Jy (BD) at 12 microns is converted to Watt/(meter^2) (IB) by the relation BD*K=IB, where K=1.348e-13 (Moshir et al 1989)." DATA_TYPE = REAL FORMAT = "E10.4" START_BYTE = 15 BYTES = 4 END_OBJECT OBJECT = COLUMN NAME = FLUX_25 UNIT = "JANSKY PER STERADIAN" DESCRIPTION = "Flux densities (1 Jy = 1.e-26 Watt/ (meter*2)Hz) are calculated from inband flux (Watts/meter^2) assuming the external source function to be proportional to 1/frequency. Jy (BD) at 25 microns is converted to Watt/(meter^2) (IB) by the relation BD*K=IB, where K=5.155e-14 (Moshir et al 1989)." DATA_TYPE = REAL FORMAT = "E10.4" START_BYTE = 19 BYTES = 4 END_OBJECT OBJECT = COLUMN NAME = FLUX_60 UNIT = "JANSKY PER STERADIAN" DESCRIPTION = "Flux densities (1 Jy = 1.e-26 Watt/ (meter*2)Hz) are calculated from inband flux (Watts/meter^2) assuming the external source function to be proportional to 1/frequency. Jy (BD) at 60 microns is converted to Watt/(meter^2) (IB) by the relation BD*K=IB, where K=2.577e-14 (Moshir et al 1989)." DATA_TYPE = REAL FORMAT = "E10.4" START_BYTE = 23 BYTES = 4 END_OBJECT OBJECT = COLUMN NAME = FLUX_100 UNIT = "JANSKY PER STERADIAN" DESCRIPTION = "Flux densities (1 Jy = 1.e-26 Watt/ (meter*2)Hz) are calculated from inband flux (Watts/meter^2) assuming the external source function to be proportional to 1/frequency. Jy (BD) at 100 microns is converted to Watt/(meter^2) (IB) by the relation BD*K=IB, where K=1.e-14 (Moshir et al 1989)." DATA_TYPE = REAL FORMAT = "E10.4" START_BYTE = 27 BYTES = 4 END_OBJECT END_OBJECT END