Follow UsHUT FITS Keywords
References and comments on FITS keywords are listed below. See main page for background.
| Keyword | Reference(s) | Comments/Notes |
|---|---|---|
| GENERAL KEYWORDS | ||
| EXTNAME | See FITS standards document. | FITS convention for naming binary table extension. MAST files use name "spectral container". |
| EQUINOX | private communication | Calculated by staff from original 1950 coordinates. |
| RADECSYS | 'FK5' | Comments here |
| TIMESYS | 'UTC' | Time system |
| MJDREF | 0.00000 | [d] MJD zero point for times |
| SPECSYS | 'TOPOCEN' | no heliocentric-correction |
| 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 | private communication (Mary Romelfanger) | Processing-Creation Date |
| VODATE | from DATE keyword | Curation Date |
| VOREF | 'http://archive.stsci.edu/vodoc/hut' | URL for Documentation |
| DS_IDENT | derived from filename | Publishers Data Set ID |
| VERSION | '1.0' | Processing Version |
| COLLECT | 'ASTRO/HUT' | Data Set Collection |
| INSTRUME | from INSTRUME keyword | Comments here |
| TELESCOP | 'HUT' | Telescope |
| FILENAME | file name | File Name |
| CR_IDENT | root name derived from filename | Internal dataset ID |
| CRETYPE | 'Archival' | Not an on-the-fly dataset |
| CURATION KEYWORDS | ||
| VOPUB | 'MAST' | VO Publishing Authority |
| AUTHOR | 'HUT 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 |
| CONTACT | 'archive help desk' | Comments here |
| 'archive@stsci.edu' | Comments here | |
| TARGET KEYWORDS | ||
| OBJECT | from OBJECT keyword | proposer's target name |
| TITLE | derived from FILENAME and OBJECT | Program Identification |
| RA_TARG | same value as used for ra (see below) | [deg] right ascension of target |
| DEC_TARG | same value used for dec (see below) | [deg] 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 HUT project web site (see http://praxis.pha.jhu.edu/science/specpg2.html | [deg] project-defined right ascension |
| DEC | same as for ra | [deg] project-defined declination |
| APERTURE | derived from SLIT keyword | [arcsec] Aperture (radius or lengthxwidth) |
| COVERAGE: TEMPORAL | ||
| DATE-OBS | from DATE-OBS keyword | UT observation start time |
| EXPOSURE | from keyword EXPOSURE | [s] exposure duration |
| TSTART | from DATE-OBS keyword (converted to MJD using IDL program juldate.pro) | [d] MJD exposure start time |
| TSTOP | TSTART + exposure | [d] MJD exposure stop time |
| TMID | average of TSTART and TSTOP | [d] MJD exposure mid time |
| COVERAGE: SPECTRAL | ||
| SPECSDIM | '1.0E-10 L' | Comments here |
| SPEC_CAL | 'Calibrated' | Calibrated spectral coordinate |
| SPEC_ERR | 0.200000 | [angstrom] Wavelength statistical error |
| SPECBAND | 'Extreme-UV,Far-UV' | Spectral Band(s) |
| SPEC_VAL | derived from data | [angstrom] Mean Wavelength |
| SPEC_BW | derived from data | [angstrom] Bandpass Width Wmax - Wmin |
| SPEC_FIL | 1.00000 | [ ] No gaps between points |
| SPEC_RP | 500 | [ ] average resolving power W/dW |
| COVERAGE: OBSERVABLE | ||
| FLUXSDIM | '1.0E+7 ML-1T-3' | Flux SIDim |
| FLUX_CAL | 'Calibrated' | Calibrated Fluxes |
| STAT_ERR | 10 | [ ] flux error in percent |
| DER_SNR | stoehr et all. 2007 Space Telescope Coordination Fac. NL 42,4. See der_snr.pdf | [ ] Derived 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 | [angstrom/pixel] Dispersion |
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