Quality Control and
Data Processing

HC PLOTS
LFC lines and orders
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 red detector with LFC in fibre A and FP in fibre B.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
none	espresso_wave_lfc_a..fiba_lfc_norder	total number of orders fitted with LFC	CAL		[docuSys coming]
none	espresso_wave_lfc_b..fibb_lfc_norder	total number of orders fitted with LFC	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 orders that are calibrated by the LFC 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 orders calibrated by LFC

The LFC operates nominally between 500 and 720 nm. This range corresponds to 32 physical orders (or 64 pipeline orders for the HR and UHR modes). The number of available orders should, therefore, not be below these values.

History

During the first months of operations (autumn 2018), the LFC was only operational during a limited number of days.

Algorithm Number of orders calibrated by LFC

The number of orders that are calibrated by the LFC is calculated by a QC procedure.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
none	espresso_wave_lfc_a..fiba_lfc_lines_tot	total number of used LFC lines	CAL		[docuSys coming]
none	espresso_wave_lfc_b..fibb_lfc_lines_tot	total number of used LFC lines	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 LFC 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 LFC lines

Not yet implemented.

History

During the first months of operations (autumn 2018), the LFC was only operational during a limited number of days.

Algorithm Number of LFC lines

The number of LFC lines is calculated by a QC procedure.