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VIMOS Quality Control:
MOS wavelength calibration

CAL | HC | refs | QC
Trending & QC1
   MOS wave
Data Package
Data Management
QC links:
dispersion rms
QC1 database (advanced users): browse | plot
   Click on CURRENT to see the current trending (Health Check).
   Click on HISTORY to see the historical evolution of the trending.

top Wavelength calibration parameters

Parameters are measured for each quadrant and for all six grisms separately.

QC1 parameters

parameter QC1 database: table, name procedure
resolution vimos_mos_wave, resol1
vimos_mos_wave, resol2
vimos_mos_wave, resol3
R = lambda/delta lambda. The spectral resolution is computed for each grism using three selected arc lamp lines with wavelengths close to the center, close to the red, and close to the blue end of the spectrum. The resolution is given by the average on all slits of the ratio between the selected arc lamp line wavelength and its FWHM (Gauss fit).
dispersion rms vimos_mos_wave, ids_rms rms of the inverse dispersion solution residuals in pixels. The residuals are the differences between the expected line positions and the actual line positions after applying the dispersion solution.


For the QC1 database (and for trending), MOS arc lamp calibrations are only considered if they are measured for calibrating science data. Results for calibrating standard star exposures differ significantly and are disregarded.


date event
2010-07 new MOS pipeline is applied; wavelength calibration is dramatically improved
2010-07 tilt of focal plane vs. detector plane, upper part of quadrant 4 is out of focus
2011-05 tilt of focal plane is fixed
2017-08, etc. some masks in quadrant 1 for a large programme were designed so that an arc line of the 2nd multiplex falls on the detector edge; that led to an artificially increased value for the dispersion RMS although the wavelength calibration is fine