Quality Control and
Data Processing

HC PLOTS
Resolving power
Dispersion solution
Number and flux of ThAR lines
QC1 database (advanced users): browse | plot
QC1 database (advanced users): browse | plot

Three different calibration sources can be used in order to wavelength calibrate ESPRESSO observations: a Fabry-Perot (FP) cavity, ThAr arc lamps, and a laser-frequency comb (LFC). The Fabry-Perot provides more than 60000 lines which are evenly distributed over the entire wavelength range of ESPRESSO. These give a very accurate relative calibration; the absolute wavelength scale has to be determined with ThAr exposures. The LFC on the other hand gives very accurate relative and absolute calibration. It covers, however, not the complete wavelength range of ESPRESSO.

A complete wavelength calibration sequence consists of:

• an exposure with FP in fibre A and fibre B
• an exposure with ThAr in fibre A and FP in fibre B
• an exposure with FP in fibre A and ThAr in fibre B
• an exposure with LFC in fibre A and FP in fibre B
• an exposure with FP in fibre A and LFC in fibre B

Wavelength calibration. Example raw frame for the blue detector with ThAr in fibre A and FP in fibre B.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
QC.ORDERS.RESOL.MEDIAN	espresso_wave_thar_a..fiba_resol_med	median resolving power of used lines for fibre A	HC		[docuSys coming]
QC.ORDERS.RESOL.MEDIAN	espresso_wave_thar_b..fibb_resol_med	median resolving power of used lines for fibre B	HC		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

Trending

The median resolving power R is trended separately for fibres A and B and for the five different combinations of resolving power and binning: HR with 1x1 and 2x1 binning, UHR with 1x1 binning, and MR with 4x2 and 8x4 binning.

Scoring&thresholds Resolving power

Scoring and thresholds have been set for R using data acquired during commissioning.

History

No particular events.

Algorithm Resolving power

The pipeline calculates the resolving power from ThAr lines. The QC parameter is the median of the values of the individual lines.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
none	espresso_wave_thar_a..fiba_disp_avg	average RMS of the dispersion solution for fibre A	CAL		[docuSys coming]
none	espresso_wave_thar_a..fiba_disp_rms	RMS of the average RMS of the dispersion solution for fibre A	CAL		[docuSys coming]
none	espresso_wave_thar_b..fibb_disp_avg	average RMS of the dispersion solution for fibre B	CAL		[docuSys coming]
none	espresso_wave_thar_b..fibb_disp_rms	RMS of the average RMS of the dispersion solution for fibre B	CAL		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

Trending

The pipeline calculates the RMS of the dispersion solution for each order. For trending, the average of these values and the RMS of the individual values are used. These are trended separately for fibres A and B and for the five different combinations of resolving power and binning: HR with 1x1 and 2x1 binning, UHR with 1x1 binning, and MR with 4x2 and 8x4 binning.

Scoring&thresholds Dispersion solution

The first and last orders on each chip have typically the highest values for the dispersion RMS. Scoring thresholds have been set for the RMS of the values per order so that a degradation of the dispersion solution for the first or last orders is flagged. Scoring of the average has been introduced so that the issues that occured in November 2020 with a new FP source, which was noisier, are flagged. Upper limits are set so that the good wavelength calibrations from March 2020 and earlier would score green.

History

No particular events.

Algorithm Dispersion solution

Pipeline calculated values per order.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
QC.THAR.LINES.NB	espresso_wave_thar_a..fiba_thar_lines_tot	total number of valid ThAr lines on fibre A	CAL		[docuSys coming]
QC.THAR.LINES.NB	espresso_wave_thar_b..fibb_thar_lines_tot	total number of valid ThAr lines on fibre B	CAL		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

Trending

The number of ThAr lines is trended separately for fibres A and B and for the five different combinations of resolving power and binning: HR with 1x1 and 2x1 binning, UHR with 1x1 binning, and MR with 4x2 and 8x4 binning.

Scoring&thresholds Number of ThAr lines

Scoring and thresholds have been set using data taken in November 2019.

History

Available since pipeline version 1.5.1, installed October 2019.

Algorithm Number of ThAr lines

The QC parameter is the total number of ThAr lines which are used for the wavelength solution.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
QC.THAR.FLUX.RATIO.MEDIAN	espresso_wave_thar_a..fiba_thar_flux_ratio	median flux ratio of ThAr lines to reference line table	CAL		[docuSys coming]
QC.THAR.FLUX.RATIO.MEDIAN	espresso_wave_thar_b..fibb_thar_flux_ratio	median flux ratio of ThAr lines to reference line table	CAL		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

Trending

The flux ratio of ThAr lines is trended separately for fibres A and B and for the five different combinations of resolving power and binning: HR with 1x1 and 2x1 binning, UHR with 1x1 binning, and MR with 4x2 and 8x4 binning.

Scoring&thresholds ThAr flux ratio

The lower threshold of 0.4 is set after a suggestion from the consortium, the upper threshold has been set using data taken in November 2019.

History

Available since pipeline version 1.5.9, installed November 2019. Pipeline version 1.5.1 had a bug in the calculation of the QC parameter.

Algorithm ThAr flux ratio

The QC parameter is the median of the flux of the ThAr lines and normalized to a reference line table.