Find information about the ESPRESSO data format here.
The following calibration data are taken as part of the ESPRESSO calibration plan.
The data types are identified by the DPR TYPE keyword in the FITS headers.
hot pixel mask
bad pixel mask
ORDERDEF,LAMP,OFF or ORDERDEF,OFF,LAMP
FLAT,LAMP,OFF or FLAT,OFF,LAMP
CONTAM,OFF,FP OR CONTAM,OFF,THAR
contamination by reference source
FP wavelength calibtation
WAVE,THAR,FP or WAVE,FP,THAR
ThAr wavelength calibration
WAVE,LFC,FP or WAVE,FP,LFC
LFC wavelength calibration
relative efficiency between fibres A and B
* N: typical number taken per night and setting
Bias, order definition, spectroscopic flat field, contamination, and
wavelength calibration frames are measured daily during
daytime as part of the calibration plan. Dark exposures and LED flat fields
are measured on a regular basis (daytime) as well as sky flat fields and flux standard
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.
The processing of ESPRESSO calibration frames requires a cascaded scheme where
the mutual dependencies of products and raw frames are respected. The proper
sequence of all these production steps is called the calibration cascade. It
is described here.