Follow UsFOS FITS Keywords
References and comments on FITS keywords are listed below. See main page for background.
| Keyword | Reference(s) | Comments/Notes |
|---|---|---|
| GENERAL KEYWORDS | ||
| EXTNAME | FITS standard keyword | Comments here |
| EQUINOX | from EQUINOX keyword | Comments here |
| RADECSYS | Russell et al. 1990, AJ 99, 2059 section IV.a based on coordinates from the HST Guide Star Catalog version 1.1 | FK4 |
| TIMESYS | from the HST keyword dictionary which was based on ICD-19 | UTC Time system |
| MJDREF | 0.00000 | [d] MJD zero point for times |
| SPECSYS | See http://www.stecf.org/poa/FOS/fos_faq.html | TOPOCENT (no velocity corrections) |
| VOCLASS | 'SPECTRUM V1.0' | VO Data Model |
| VOSEGT | 'SPECTRUM' | Segment type |
| DATALEN | derived from data | [ ] Number of points in spectrum |
| DSSOURCE | 'POINTED' | Survey or Pointed |
| DATA ID KEYWORDS | ||
| DATE | from DATE keyword | Processing-Creation Date |
| VODATE | from IDL "today" command | Curation Date |
| VOREF | 'http://archive.stsci.edu/vodocs/hst/fos' | URL for Documentation |
| DS_IDENT | 'ads/sa.hst#y19g0205t' | Publishers Data Set ID |
| VERSION | '1.0' | Processing Version |
| COLLECT | 'HST/FOS' | Data Set Collection |
| INSTRUME | hardcoded value | Instrument (FOS) |
| TELESCOP | hardcoded value | Telescope (HST) |
| FILENAME | derived from ROOTNAME keyword | File Name |
| CR_IDENT | derived from ROOTNAME keyword | Internal dataset ID |
| CRETYPE | 'Archival' | Not an on-the-fly dataset |
| CURATION KEYWORDS | ||
| VOPUB | 'MAST' | VO Publishing Authority |
| AUTHOR | 'HST project' | Creator |
| VOPUBID | 'ivo://mast.stsci.edu' | URI for VO Publisher |
| VOLOGO | 'http://archive.stsci.edu/images/100.mastlogo.gif' | MAST logo |
| VOVER | '1.0' | VO Curation version |
| VORIGHTS | 'PUBLIC' | Data is public |
| CONTRIB1 | The HST proposal ID is used as specified in the PROPOSID keyword. | PEP proposal identifier |
| CONTACT | archive help desk | Comments here |
| archive@stsci.edu | Comments here | |
| TARGET KEYWORDS | ||
| OBJECT | from TARGNAME keyword | proposer's target name |
| TITLE | derived from ROOTNAME and TARGNAME keywords | title = "filename, object name" |
| RA_TARG | from RA_TARG keyword | right ascension of target |
| DEC_TARG | from DEC_TARG keyword | declination of target |
| WCS Paper 3 Keywords | ||
| 1S2_1 | 'WAVE' | Column name with spectral coordinates |
| 1CYTP2 | 'WAVE-TAB' | Spectral coordinate is wavelength |
| 1S3_1 | 'WAVE' | Column name with spectral coordinates |
| 1CYTP3 | 'WAVE-TAB' | Spectral coordinate is wavelength |
| COVERAGE: SPATIAL | ||
| RA | from RA_APER keyword | right ascension of aperture |
| DEC | from DEC_APER keyword | declination of aperture |
| APERTURE | aperture name obtained from APER_ID and dimensions obtained from and slit dimensions from FOS Instrument Handbook (with COSTAR corrections made using DATE-OBS value) | [arcsec] Aperture (width or lengthxwidth) |
| COVERAGE: TEMPORAL | ||
| DATE-OBS | from DATE-OBS and TIME-OBS keywords | UT observation start time |
| EXPOSURE | from EXPTIME keyword | [s] exposure duration |
| TSTART | from EXPSTART keyword | [d] MJD exposure start time |
| TSTOP | from EXPEND keyword | [d] MJD exposure stop time |
| TMID | derived from EXPSTART & EXPEND | [d] MJD exposure mid time |
| COVERAGE: SPECTRAL | ||
| SPECSDIM | '1.0E-10 L' | Comments here |
| SPEC_CAL | private communication Dorothy Fraquelli | Calibrated spectral coordinate |
| SPEC_ERR | From FOS Instrument Handbook (see notes) | [angstrom] Wavelength statistical error |
| SPECBAND | Based on derived wavelength range and classifications by Paolo Padovani using MAST IDL program vo_specband | Spectral Band(s) Far-UV and Near-UV |
| SPEC_VAL | derived from data | [angstrom] Mean Wavelength |
| SPEC_BW | derived from data | [angstrom] Bandpass Width Wmax - Wmin |
| SPEC_FIL | HST Data Handbook Vol II, Heritage Instruments, Chapt 29, section 29.3.9, Data Acquisition Fundamentals | 1.0 No gaps between points |
| SPEC_RP | From FOS Instrument Handbook (see notes) | [ ] average resolving power W/dW |
| COVERAGE: OBSERVABLE | ||
| FLUXSDIM | '1.0E+7 ML-1T-3' | Flux SIDim |
| FLUX_CAL | based on AIS_CORR and FLX_CORR keywords (private communication Dorothy Fraquelli) | Calibrated and uncalibrated fluxes (most uncalibrated spectra are wavecals) |
| STAT_ERR | From FOS Instrument Handbook (see notes) | [ ] flux error in percent |
| DER_SNR | derived from data using algorithm described in Stoehr et al 2007 Space Telescope Coordination Fac. NL, 42, 4 | [ ] Mean signal-to-noise ratio |
| FLUXAVG | derived from data | [erg/cm**2/s/angstrom] Average Flux |
| FLUXMAX2 | derived from data | [erg/cm**2/s/angstrom] 98% Maximum Flux |
| SPECDISP | derived from data (Wmax-Wmin)/npts | [angstrom/pixel] Dispersion |
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