This file details the pointing history of the prime instrument during an observation at a rate of two records per secondD.2. Any drift in the pointing is reflected in this file. In anticipation of possible future work, the IIPH's binary table contains all the attitude-related quantities that could conceivably have been variable with time, including, in particular, the Star-Tracker/Quadrant Star Sensor (STR/QSS) misalignment quaternion (MISQ). This misalignment is subject to change due to thermal effects and was thus recalibrated at the beginning of each revolution, though the day-to-day changes were small (less than one arcsecond). The changes during a single revolution, which would cause instruments' pointing direction to drift, were probably even smaller. Although it was not possible to estimate the magnitude of any such drift in routine operations, so that the elements of MISQ are constant in the distributed IIPH files, detailed analysis of high-resolution CAM or SWS data might allow the drift history to be estimated, yielding the evolution of the MISQ.
The IIPH file contains a primary header with the fields described in Table D.30. In this example non-mandatory fields are filled with example values.
| Keyword | Value | Description |
| SIMPLE = | T | / File does conform to FITS standard |
| BITPIX = | 8 | / Number of bits per data pixel |
| NAXIS = | 0 | / Number of data axes |
| EXTEND = | T | / FITS dataset may contain extensions |
| ORIGIN = | 'ESA ' | / European Space Agency |
| TELESCOP = | 'ISO ' | / Infrared Space Observatory |
| COMMENT | Instrument Instantaneous Pointing History | |
| FILENAME = | 'IIPH64001226' | / File name in ISO archive |
| DATE = | '18/08/97' | / Creation date |
| FILEVERS = | '0518 ' | / Version ID in ISO archive |
| OLPVERS = | 'OLP_611 ' | / SOC OLP system version |
| CALGVERS = | 'CALG_31 ' | / SOC OLP CAL-G files version |
| USERNAME = | 'PIPELINE' | / |
| CREATOR = | 'DERIVE_IPH v6.2' | / Application that created the file |
INSTRUME = |
'PHT ' | / Instrument identifier |
ATTRA = |
266.56054 | / Intended Instrument J2000 Right Ascension (degrees) |
| ATTDEC = |
+62.45108 | / Intended Instrument J2000 Declination (degrees) |
ATTTYPE = |
'R ' | / Type of attitude operation |
| ATTOTFTH = | 2.0 | / On-target threshold (arcsec) |
| ATTRNPTS = | 3 | / Number of points per raster line |
| ATTRNLNS = | 3 | / Number of raster lines |
| ATTRDPTS = | 92 | / Distance between adjacent points (arcsec) |
| ATTRDLNS = | 92 | / Distance between adjacent lines (arcsec) |
| ATTRORIE = | 1 | / Raster orientation flag (0 or 1) |
| ATTRROTA = | 0.0 | / Rotation of raster pattern (degrees) |
| ATTGUIDE = | 93715 | / Guide star reference number |
| ATTSAANG = | 88.7 | / Solar aspect angle (degrees) |
| ATTERROR = | 0 | / 0=OK, 1=target not acquired, |
| 2=No STR/QSS misalignment | ||
| ATTMISQ1 = | 0.0000000 | / STR/QSS misalignment quaternion Q(1) |
| ATTMISQ2 = | -0.0004555 | / STR/QSS misalignment quaternion Q(2) |
| ATTMISQ3 = | -0.0002231 | / STR/QSS misalignment quaternion Q(3) |
| ATTMISQ4 = | 0.9999999 | / STR/QSS misalignment quaternion Q(4) |
| ATTINSQ1 = | 0.0000000 | / QSS/Instrument alignment quaternion Q(1) |
| ATTINSQ2 = | -0.0000181 | / QSS/Instrument alignment quaternion Q(2) |
| ATTINSQ3 = | 0.0012427 | / QSS/Instrument alignment quaternion Q(3) |
| ATTINSQ4 = | 0.9999992 | / QSS/Instrument alignment quaternion Q(4) |
| INSTRA = | 266.13155 | / Reference instrument J2000 right ascension (degrees) |
| INSTDEC = | +62.42157 | / Reference instrument J2000 declination (degrees) |
| INSTROLL = | 127.70 | / Reference instrument J2000 roll angle (degrees) |
| CINSTRA = | 266.13155 | / Corrected reference instrument J2000 right ascension |
| CINSTDEC = | +62.42157 | / Corrected reference instrument J2000 declination |
| CINSTROL = | 127.70 | / Corrected reference instrument J2000 roll angle |
| VERS1 = | '0518/IRPH08300207' | / Version ID of each input file |
| VERS2 = | '0518/AOCS08300207' | / Version ID of each input file |
Each record in the IIPH file has the fields described in Table D.31. All observations will result in a file of many entries - two every second.
| Keyword | Number | Format | Description |
| UTK | 1 | I4 | UTK time key |
| UTC | 2 | I4 | UTC time key |
| RPID | 2 | I1 | Raster pointer ID |
| APERTURE |
1 | A2 | Aperture in use |
| OTF | 1 | I1 | On-target flag. 0=Off target, 1=On target |
| FILTER | 1 | I1 | Attitude filter applied. 0=None, 1=AOCS, |
| 2=Other | |||
| SPIKE | 1 | I1 | Attitude spike flag. 0=OK, 1=warning, |
| 2=not defined | |||
| SPARE | 13 | I1 | Spare space |
| ATTQ | 4 | R8 | Instantaneous attitude quaternion |
| RA |
1 | R8 | Right ascension, in degrees |
| DEC |
1 | R8 | Declination, in degrees |
| ROLL |
1 | R8 | Roll angle, in degrees |
| CORQ | 4 | R8 | Corrected attitude quaternion |
| CRA | 1 | R8 | Corrected right ascension, in degrees |
| CDEC | 1 | R8 | Corrected declination, in degrees |
| CROLL | 1 | R8 | Corrected roll angle, in degrees |
| STRQ | 4 | R8 | Instantaneous Star-Tracker quaternion |
| XRA | 1 | R8 | Instantaneous right ascension, in degrees |
| XDEC | 1 | R8 | Instantaneous declination, in degrees |
| XROLL | 1 | R8 | Instantaneous roll angle, in degrees |