Quality Control and
Data Processing

HC PLOTS
resolving power
arc line flux
dispersion
QC1 database (advanced users): browse | plot

IRDIS LSS mode wavelength calibration spectra raw frames are acquired in LSS mode and show arc line spectra. Spectra come in two different dispersive optical elements: GRI_MRS and PRI_LRS. They can be combined with the narrow slit of slit width = 0.09'' identified in the header via INS4.OPT11.NAME = SLIT_NL or the more frequently used wide slit (0.12'') with INS4.OPTI11.NAME = SLIT_WL. The following plots are for the SLIT_WL.

There are six monochromatic laser lamps, each once produces one arc line in the spectrum at the following nominal wavelengths:

0.9877 mu, 1.1237 mu, 1.3094 mu and 1.5451 mu, 1.730 mu ands 2.015 mu

The pipeline recipe generates a product with PRO.CATG=IRD_WAVECALIB to be used to calibrate science spectra which is analyzed by QC scripts in the following.

	Arc spectrum of the IRDIS wavelength product for GRI_MRS with six arc lines. Left channel and right channel with coronographic mask
	Arc spectrum of the IRDIS wavelength product for PRI_LRS with six arc lines. Left channel and right channel with coronographic mask

	Median arc spectrum of the left channel IRDIS wavelength cube product for GRI_MRS with six arc lines. Each arc line is fit by a Gaussian to monitor resolving power, arc line flux and measured wavelength.
	Median arc spectrum of the left channel IRDIS wavelength cube product for PRI_LRS with six arc lines. Each arc line is fit by a Gaussian to monitor resolving power, arc line flux and measured wavelength.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
[QC script]	sphere_irdis_wave..respow1	laser lamp1 arc line respow	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..respow2	laser lamp2 arc line respow	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..respow3	laser lamp3 arc line respow	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..respow4	laser lamp4 arc line respow	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..respow5	laser lamp5 arc line respow	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..respow6	laser lamp6 arc line respow	HC		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

The QC script analyses the median extracted spectrum out of the pipeline product. Each arc line is fit by a Gaussian and the best fit sigma is scaled to a FWHM ans is divided by the central arc line wavelength. By this, from each arc line a value of the resolving power is retrieved. The resolving power of the individual arc line show a linear dependence on the wavelength.

Arc calibration frames are acquired with the (homogeneously illuminated) SLIT_WL setup corresponding to a slit width of 120 mas and result in a slit-width limited resolving power of 24 and 200. Point-source on-the-sky objects with a diffraction-limited size of ~50 mas result in a higher spectral resolving powers.

	GRI_MRS: Zoom of the six arc lines (black) with Gaussian fit. Note that the arc line PSF has some residual box-shape from the slit, meaning the instrumental profile is not fully resolved.
	PRI_LRS: Zoom of the six arc lines (black) with Gaussian fit. Note that the arc line PSF has some residual box-shape from the slit, meaning the instrumental profile is not fully resolved.

	GRI_MRS: Resolving power as a function of wavelength.
	PRI_LRS: Resolving power as a function of wavelength.

Trending

The resolving power of the six arc lines at is monitored for the 120 mas and the 90 mas slit. Where the 90 mas slit is used very rarely.

Scoring&thresholds IRDIS LSS resolving power

All QC parameters are not scored.

History

• 2019-05-27: The QC script was put in operation. All hitherto acquired LSS wavelength calibrations have been reprocessed with pipeline version 0.38 and the QC script.

Algorithm IRDIS LSS resolving power

The QC script fits a Gaussian to each of the monochromatic laser lamp arc lines. Best fit values of sigma, total flux, central wavelength and derived dispersion are stored and monitored.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
[QC script]	sphere_irdis_wave..flux1	laser lamp1 arc line flux	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..flux2	laser lamp2 arc line flux	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..flux3	laser lamp3 arc line flux	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..flux4	laser lamp4 arc line flux	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..flux5	laser lamp5 arc line flux	HC		[docuSys coming]
[QC script]	sphere_irdis_wave..flux6	laser lamp6 arc line flux	HC		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

The QC script analyses the median extracted spectrum out of the pipeline cube product. Each arc line is fit by a Gaussian and the best fit sigma is scaled to a FWHM an divided by the central arc line wavelength. By this, from each arc line a value of the resolving power is retrieved. The integrated flux of the Gaussian fit is stored.

Trending

The flux of each arc line is monitored.

Scoring&thresholds IRDIS LSS arc line flux

The QC parameters are not scored.

History

• 2019-07 Script put in operation after having verfied that the dispersion retrived from the product image matched the results of the QC script.

Algorithm IRDIS LSS arc line flux

The QC script fits a Gaussian to each of the monochromatic laser lamp arc lines.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
[QC script]	sphere_irdis_wave..dispersion	linear dispersion [mu/wlenbin]	HC		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

	GRI_MRS: Linear dispersion relation (green line) derived from the fitted arc lines (red dots), compared with the pipeline product extension #6, which uses a second order polynomial.
	PRI_LRS: Linear dispersion relation (green line) derived from the fitted arc lines (red dots), compared with the pipeline product extension #6, which uses a second order polynomial.

Trending

The pipeline does not document the derived dispersion solution. For this reason the six arc line (Gaussian fit) centers are use to derive a linear dispersion solution. This linear dispersion solution and its offset in pixel is monitored. See QC1 Plotter.

Scoring&thresholds IRD dispersion

QC parameters are not scored.

History

In 2018 the QC scripts have been tested and in 2019-04 put in operation in order to monitor the health of the instrument. In 2019 the QC scripts have been improved to become robust against wavelength shift of more than 10 pixel.

Algorithm IRD dispersion

The best fit positions of arc arc lines and their wavelength bins are used to derive a linear regression to retrieve the wavelength of the first wavelength bin and the dispersion in mu/wlenbin.