Table Formats

MIDAS table files are used to store relevant information in tabular form. Four types of tables are considered. The first two, tables order.tbl and line.tbl, are operational tables generated by the user during the session. The other two types of tables are provided by the system to calibrate the data in wavelength and flux.

order.tbl -- Contains echelle orders. This table contains the coefficients a_ij in relation 7.2 stored as descriptors. The table is created by the command DEFINE/ECHELLE or DEFINE/HOUGH

back.tbl -- Contains information related to the background reference positions. This table is created by the command PREPARE/BACKGROUND which is called by DEFINE/ECHELLE and DEFINE/HOUGH.

line.tbl -- Contains information related to the position of the calibration lines. This table contains the dispersion coefficients for each spectral order, stored as descriptors after the line identification process. It is generated by the command SEARCH/ECHELLE and extended and updated by the command IDENTIFY/ECHELLE.

Line Catalogue

-- Contains the wavelength calibration lines. There are several line catalogues available in instrument related system area, like MID_CASPEC and MID_EFOSC.

Standard Stars

-- Contains the fluxes of standard stars in different units. These tables are copied automatically from the area MID_STANDARD into the user work space with the command SET/ECHELLE FLUXTAB=name

 

Unit Description

ORDER - sequential order number

X PIXEL sample (x-axis) position of the order

Y PIXEL line (y-axis) position of the order

YFIT PIXEL fitted line (y-axis) position of the order

RESIDUAL PIXEL residual (Y-YFIT) 3|c|Table back.tbl

Unit Description

ORDER - sequential order number

X PIXEL sample (x-axis) position of the order

YBKG PIXEL line position of the background above the order

BKG DN value of the background 3|c|Table line.tbl

Unit Description

X PIXEL sample (x-axis) position of the line

Y PIXEL relative order number

PEAK DN estimated line maximum

YNEW PIXEL line (y-axis) position of the line

ORDER - spectral order number

IDENT ANGSTROM manual identification

WAVEC ANGSTROM computed wavelength

RESIDUAL ANGSTROM residual (WAVEC-WAVE) 3|c|Line Catalogue

Unit Description

WAVE ANGSTROM wavelength 3|c|Standard Star Atlas

Unit Description

MAGNITUDE - magnitude

WAVE ANGSTROM wavelength

BIN_W ANGSTROM bin width

FLUX_W ERGS/S/CM/CM/ANG flux