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| QC PLOTS |
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CURRENT |
HISTORY |
| optical distortion |
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| effective optical distortion |
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| grating, dispersion |
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| arc lamps |
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| QC1 database (advanced users):
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plot
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Click on CURRENT to see the current trending (Health Check).
Click on HISTORY to see the historical evolution of the trending. |
Arc calibrations come for two gratings (LR and MR) and two instrument arms (SW and LW), thus one may find the following abbreviations:
- SSAL short wavelength spectroscopy arcs using the LR grating
- SSAM short wavelength spectroscopy arcs using the MR grating
- LSAL long wavelength spectroscopy arcs using the LR grating
- LSAM long wavelength spectroscopy arcs using the MR grating
The isaacp arc recipe was considerably improved and was put in operation for data taken after 2003-11-20. The arc recipe produces two kind of coefficients: a) the wavelength dispersion coefficients (3 parameters) and b) the optical distortion in x-direction for the whole field of view (6 parameters).
The QC parameters for the wavelength solution are : QC.DISPC01, QC.DISPC02 and QC.DISPC03, where
lambda=QC.DISPC01 + X * QC.DISPC02 + X * X * QC.DISPC03 + X * X * X * QC.DISPC04
holds. The QC parameter of the optical distortion in x directions are related via :
DeltaX=QC.DIST1 + X * QC.DISTX + Y * QC.DISTY + X * Y * QC.DISTXY + X * X * QC.DISTXX + Y * Y * QC.DISTYY
The QC parameters of the optical distortion in y-direction are derived from a different kind of calibrations: startrace frames.
The LR grating recipe generates two products, one for the Ar lamp and one for the Xe lamp separately.
The MR grating recipe generates one product with lines of both lamps.
The pipeline recipe processes the arc frames in two parts. The first part is on the arc line detection and the correction of the optical distortion in x-direction. The second part is on the arc line identification via the arc line catalog and calculating the non-linear wavelength dispersion transformation.
QC1 parameters
| parameter |
QC1 database: table, name |
procedure |
optical distortion coefficients
SW-arm
LW-arm |
isaac_arc, qc_dist1, qc_distx, qc_disty, qc_distxx, qc_distxy, qc_distyy |
- After arc lines have been detected the curvature is modeled by a polynomial and correct to get straight lines. At least three emission lines must be detected. The polynomial describes the optical distortion in x-direction only. The optical distortion correction in y-direction is not required in this calibration step. See startrace calibrations for details on the optical distortion in y-direction. |
effective optical distortions
SW-arm
LW-arm |
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- As good practice the optical distortion coefficients are applied to five selected points in the FOV. These are the four detector quadrant centers (ul,ur, ll, lr) and the center of the detector (cc). These effective distortions are not stored in the DB. They are calculated on the fly, when the health check plot is updated. |
| arc line number |
isaac_arc, qc_arcs_num |
- the number of detected arc lines |
| number of arc lines with fwhm |
isaac_arc, qc_arcs_numgood |
- the number of detected arc line for which a fwhm could be calculated |
| FWHM |
isaac_arc, qc_fwhm_med |
- the median fwhm of qc_arcs_numgood arc lines |
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top
wavelength dispersion parameters |
Example QC reports showing the arc line spectrum (red) and the catalog lines with their relative strength (blue symbols) for the setting SW LR SK are given once for the
Xenon lamp  and once for the Argon lamp  .
QC1 parameters
| parameter |
QC1 database: table, name |
procedure |
| wavelength of first pixel |
isaac_arc, qc_dispco1 |
- offset coefficient of the wavelength dispersion solution |
| dispersion |
isaac_arc, qc_dispco2 |
- linear coefficient of the wavelength dispersion solution |
| non-linear dispersion |
isaac_arc, qc_dispco3 |
- quadratic term of the wavelength dispersion solution |
| non-linear dispersion |
isaac_arc, qc_dispco4 |
- cubic term of the wavelength dispersion solution |
| wavelength of pixel 512 |
isaac_arc, qc_wlen |
- central wavelength |
| correlation factor |
isaac_arc, qc_xcorr |
- the correlation coefficient of the pattern matching algorithm. qc_xcorr >= 50% means the correct solution is found. qc_xcorr >=90% means the errorbars of the fit are very small. |
| solution quality |
isaac_arc, qc_disp_stdev |
- standard deviation of the line position differences |
| lines in catalog |
isaac_arc, qc_disp_numcat |
- number of arc lines in the catalog within wavelength range |
| used lines for correlation |
isaac_arc, qc_disp_match |
- number of arc lines in the catalog within wavelength range used for the correlation |
| grating offset |
isaac_arc, qc_pixoff |
- grating offset in pixel (difference between QC.WLEN and INS.GRAT.WLEN) |
| resolving power |
isaac_arc, qc_respow |
- resolving power (QC.WLEN / QC.FWHM.MED) |
| arc line flux |
isaac_arc, qc_arc_line_flux |
- resolving the post pipeline script searches for each of the four SW-LR settings a certain xenon and an argon arc line and extracts the flux from the pipeline product table. The used lines are:
Argon 1.054810 mu (SW-LR-SZ)
Argon 1.208810 mu (SW-LR-J)
Argon 1.744926 mu (SW-LR-SH)
Argon 2.313952 mu (SW-LR-SK)
Xenon 1.202994 mu (SW-LR-J)
Xenon 1.510384 mu (SW-LR-SH)
Xenon 2.380295 mu (SW-LR-SK) |
Trending
The following relations between different QC1 parameters are trended:
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