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GHRS 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 table extension (i.e., 'spectral container')
EQUINOX from EQUINOX keyword Comments here
RADECSYS Russell et al 1990 AJ, 99, 2059 section IV a FK4
TIMESYS GHRS Handbook, version 6, June 1995 Chapt 2, Time resolution UTC
MJDREF 0.00000 [d] MJD zero point for times
SPECSYS GHRS Handbook, version 6, June 1995 Soderblum, et. al. heliocentric wavelengths
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/vodoc/hst/hrs' URL for Documentation
DS_IDENT 'ads/sa.hst#z3lp110ht_vo.fits' Publishers Data Set ID
VERSION '1.0' Processing Version
COLLECT 'HST/GHRS' Data Set Collection
INSTRUME 'GHRS' Instrument
TELESCOP 'HST' Telescope
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 'archive.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 from PROPOSID keyword PEP proposal identifier
CONTACT 'archive help desk' Comments here
EMAIL 'archive@stsci.edu' Comments here
TARGET KEYWORDS
OBJECT from TARGNAME keyword proposer's target name
TITLE derived from ROOTNAME and TARGNAME filename, object
RA_TARG from RA_TARG keyword [deg] right ascension of target
DEC_TARG from DEC_TARG keyword [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 RA_APER keyword [deg] right ascension of aperture
DEC from DEC_APER keyword [deg] declination of aperture
APERTURE from APERTURE keyword (aperture name) and GHRS handbook(?) to convert aperture name to slit dimensions in arcsec, (with corrections made for COSTAR based on DATE-OBS value) Aperture (width or lengthxwidth in arcsec) Some wavecals list aperture=0.
COVERAGE: TEMPORAL
DATE-OBS from DATE-OBS and TIME-OBS keywords UT observation start time
EXPOSURE from EXPTIME keyword [sec] exposure duration
TSTART from EXPSTART keyword [d] MJD exposure start time
TSTOP from EXPEND keyword [d] MJD exposure stop time
TMID derived from EXPSTART and EXPEND [d] MJD exposure mid time
COVERAGE: SPECTRAL
SPECSDIM '1.0E-10 L' Comments here
SPEC_CAL Calibrated spectral coordinate
SPEC_ERR GHRS Handbook Version 6, Chapt 5, June 2005 [angstrom] Wavelength statistical error
SPECBAND Based on derived wavelength range and classification by Paolo Padovani using the IDL program vo_specband Spectral Band(s)
SPEC_VAL derived value [angstrom] Mean Wavelength
SPEC_BW derived value [angstrom] Bandpass Width Wmax - Wmin
SPEC_FIL HST Data Handbook, section 34.2.2 1.0 No gaps between points
SPEC_RP GHRS Handbook Version 6, Chapt. 2, June 2005 average resolving power W/dW
COVERAGE: OBSERVABLE
FLUXSDIM '1.0E+7 ML-1T-3' Flux SIDim
FLUX_CAL based on keyword FLX_CORR (private communication Dorothy Fraquelli) Fluxes are either absolute or uncalibrated (mostly wavecals)
STAT_ERR GHRS Handbook Verson 6, Chapt. 2, June 2005 10% flux error
DER_SNR derived value, see Stoehr et al. 2007 Space Tele. Coord. 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