This file contains information on the operational Star-Tracker.
The ISTR file contains a primary header with the fields described in Table D.34. In this example non-mandatory fields are filled with example values.
| Keyword | Value | Description |
| SIMPLE = | T | / |
| BITPIX = | 8 | / |
| NAXIS = | 0 | / |
| EXTEND = | T | / |
| ORIGIN = | 'ESA ' | / European Space Agency |
| TELESCOP = | 'ISO ' | / Infrared Space Observatory |
| COMMENT | ISO Star-Tracker calibration data | |
| FILENAME = | 'ISTR' | / File name in ISO archive |
| DATE = | '09/07/95' | / Creation date |
| FILEVERS = | '0298 ' | / Version ID in ISO archive |
| OLPVERS = | 'OLP_21 ' | / SOC OLP system version |
| CALGVERS = | 'CALG_31 ' | / SOC OLP CAL-G files version |
| USERNAME = | 'PIPELINE' | / |
| DATE-OLD = | '1997-07-14' | / Date of original creation by IDT |
The ISTR file contains records described in Table D.29.
| Keyword | Number | Format | Description |
| F | 1 | R8 | Focal length, in metre |
| DFY | 1 | R8 | Focal length fractional error Y-component |
| DFZ | 1 | R8 | Focal length fractional error Z-component |
| X10 | 1 | R8 | FSS-Z misalignment parameter |
| DX10 | 1 | R8 | FSS-Z misalignment parameter error equivalent angle, in arcsec |
| STRX | 1 | R8 | STR-X misalignment, in degrees |
| DSTRX | 1 | R8 | STR-X misalignment error, in arcsec |
| REV | 1 | I4 | Revolution after which the measurements apply |
| UTC | 1 | I4 | UTC after which the measurements apply, in seconds since 1989.0 |
| SPARE | 16 | I1 | Spare space |