[Top] [Prev] [Next] [Bottom]
31.3 CDBS Reference Relations
The CDBS relations for the FOS reference files and reference tables are described below. Note that these are relations that point to the reference files and tables: they do not contain the data used. Multiple entries are allowed for each reference file or table type which are distinguished by effective (or USEAFTER) date.
The cyccs2r table values were never formally confirmed after science verification
(SV). This had little or no practical impact as, only a few sky observations were
taken, none of which were intended to aid the proposed science.
- cyccs3r: Filter widths used for smoothing the sky or background spectra.
- cyccs4r: Polarimetry information regarding waveplate pass direction angles, initial waveplate position angles, the pixel number at which the wavelength shift between the two pass directions is to be determined for computing the merged spectrum, and the phase and amplitude coefficients for correction of polarization angle ripple.
- cyccs5r: The shift in pixels to be applied to the sky spectrum before subtraction.
- cyccs6r: Dispersion coefficients to generate wavelength scales. There is one entry for each detector, disperser, aperture, and polarizer combination.
- cyccs7r: GIM correction scale factors used to scale the modeled shift of the spectrum due to the earth's magnetic field.
- cyccs8r: Predicted background count rates as a function of geomagnetic position used to scale the background reference file.
- cyccs9r: Un-illuminated diode ranges for each detector and grating combination. Used to determine the background scattered light.
- cyccsar: List of OTA focus positions versus time. Used to correct for aperture sensitivity dependent on focus position.
- cyccsbr: As a function of detector and disperser combination, coefficients to normalize aperture throughputs to the -reference aperture used to determine the average inverse sensitivity -calibration.
- cyccscr: Throughput corrections versus focus as a function of the combination of detector, disperser, and aperture.
- cyccsdr: As a function of detector and disperser combination, throughput correction factors to account for changes in -instrument sensitivity over time.
- coccg2r: Paired pulse correction table used to correct for non-linear response of the diode electronics. Both detectors have the same correction constants, which are time independent. This table is shared with GHRS.
- cybacr: This relation is for the background reference files. For each detector there is one file that is used as a default background count rate in the event no background spectra were observed.
- cyfltr: This relation is for the flatfield reference files. These files are used to remove the small scale diode and photocathode non-uniformities. There are separate files for each detector, disperser, aperture, and polarizer combination.
- cyivsr: (polarimetry only) This relation is for inverse sensitivity reference files. These files are used to convert corrected count rates to absolute flux units. There are separate files for each detector, disperser, aperture and polarizer combination.
Figure 31.3: Pre-COSTAR Inverse Sensitivity -Curves for Red High -Dispersion -Gratings
Figure 31.4: Post-COSTAR Sensitivity Curves for High Dispersion -Gratings
Figure 31.5: Post-COSTAR Sensitivity Curves for Low Dispersion -Gratings
Figure 31.6: Retardation Reference Files
Figure 31.7: Example of a Pre-COSTAR Point Spread Function for the FOS
Figure 31.8: Example of a Pre-COSTAR Line Spread Function for the FOS
[Top] [Prev] [Next] [Bottom]
Copyright © 1997, Association of Universities for Research in Astronomy. All rights
Last updated: 01/14/98 14:47:13