CCSD3ZF0000100000001NJPL3IF0PDSX00000001
PDS_VERSION_ID		       = PDS3
RECORD_TYPE                    = STREAM 
SPACECRAFT_NAME                = "INFRARED ASTRONOMICAL SATELLITE"
INSTRUMENT_NAME                = "FOCAL PLANE ARRAY"
INSTRUMENT_ID                  = FPA
OBJECT                         = TEXT 
  NOTE                         = "Information about the IRAS Scan  
   History File and the IRAS Zodiacal History binary file indices."
  PUBLICATION_DATE             = 1994-07-22 
END_OBJECT                     = TEXT 
END 

This directory contains the IRAS Scan History File, its PDS label, the low 
resolution Zodiacal History binary file index, its PDS label, the medium 
resolution Zodiacal History binary file index, and its PDS label. The IRAS 
Scan History file includes all of the pointing information of the Infrared 
Astronomical Satellite over the span of its mission. It is broken down into 
5749 scans, each of which has a unique observing geometry.  The Zodiacal 
History binary file indices contain locations of data within the binary
datasets.

SCAN.TAB 	- IRAS Scan History File

The first column of the table SCAN.TAB contains the OBSERVATION_ID of a 
scan. This id is given in the form SSS.OO, where SSS denotes the IRAS 
Satellite Observation Plan (SOP) and OO denotes the observation number 
within a SOP.

ZOHF low resolution data for an observation with id xxx.yy can be found 
in ASCII form in the file A_xxx_yy.TAB , found in the subdirectory 
/ZOHF1.

ZOHF medium resolution data for an observation with id xxx.yy can be 
found in ASCII form in the file B_xxx_yy.TAB , found in the 
subdirectory /ZOHF2.

A binary version of the low resolution data for an observation can be 
found in the file /BIN_DATA/ZOHF1.DAT .  Note that OBSERVATION_ID is 
also a column in the data file.

A binary version of the medium resolution data can be found in 
/BIN_DATA/ZOHF2.DAT .

ZOHF_LOW.TAB     - Index for the IRAS Low Resolution Zodiacal History Files 
                   in binary form.

ZOHF_MED.TAB     - Index for the IRAS Medium Resolution Zodiacal History Files 
                   in binary form.

The Zodiacal History binary file indices contain the OBSERVATION_ID of the 
table, the start byte of each scan, and the number of records contained
within the table for each scan.  The OBSERVATION_ID can be cross referenced
with SCAN.TAB to find the pointing geometry for the given OBSERVATION_ID.