Session Parameters

 

 

INSTR Defines the spectrograph (e.g. CASPEC, EFOSC).

GRATING Defines the grating or instrument configuration.

CCD Defines the CCD.

CCDBIN Binning factor along X and Y. This parameter has impact on the wavelength calibration.

SCAN Limits of the scanned area of the CCD. This parameter has impact on order definition (method Hough) and background estimates.

ORDREF Order reference frame

DEFMTD Order definition method (STD, COM, HOUGH).

DEFPOL Degree of the bivariate polynomial used in the definition of the orders, see Section 7.2.

WIDTH1 Defines the width in pixels of the orders perpendicular to the dispersion direction. It is used to detect the orders as described in Section 7.2 (methods STD, COM). Typical values are between 2 and 15, depending on the observing slit.

THRES1 Defines the threshold to detect orders on the order reference image as described in Section 7.2 (methods STD, COM).

SLOPE Mean slope of the orders in pixel space (methods STD, COM).

 

NBORDI Number of orders to be detected (method HOUGH).

WIDTHI This parameter is used to remove the traces of the orders in Hough space during the detection. Its minimum value is the half-width in pixels of the orders perpendicular to the dispersion direction. Its maximum value is the interorder distance minus the half-width of the orders (method HOUGH).

THRESI Defines the threshold for the order detection (equivalent to THRES1)

WLC Raw wavelength calibration image.

LINCAT System table with comparison lines.

EXTMTD Extraction method (AVERAGE, LINEAR, OPTIMAL).

SLIT Width of the extraction slit in pixels.

OFFSET Offset of the extraction slit. The offset is given in pixels, positive values are above the center and negative offsets are below the center of the orders as shown in the image monitor (command LOAD/ECHELLE).

SEAMTD Searching method (GAUSSIAN, GRAVITY). This parameter controls the definition of the center of the calibration lines.

WIDTH2 Defines the width of the calibration lines in pixels.

THRES2 Defines the threshold above the local background to detect comparison lines. The actual value should be chosen to detect about 10 to 20 lines per order.

WLCMTD Wavelength calibration method (PAIR, ANGLE, TWO-D, GUESS, RESTART, ORDER). This parameter controls the execution of IDENTIFY/ECHELLE.

WLCOPT Dispersion relation option (1D, 2D)

GUESS Optional reference to a previous session with the same instrument configuration, to be used as a guess for the dispersion coefficients (required if WLCMTD=GUESS).

WLCVISU Visualisation of intermediate results (YES/NO).

DC Is the degree of the polynomial used in the dispersion relation, see Section 7.6.

TOL Defines a tolerance window for the last step of single-order computation of the dispersion relations.

WLCLOOP Three parameters to control the iterative identification of lines by improvement of a global solution.

WLCNITER Two parameters for the minimum and maximum number of iterations of the identification loop.

 

FFOPT Flat-Fielding option (YES/NO). If the value NO is assigned to this paramter, no Flat-Field correction is performed

FLAT Raw flat field image.

CORRECT Flat field correction image.

BLAZE Smoothed flat field used in the normalisation of the flat field.

BKGMTD Background estimation method (POLY, SPLINE, SMOOTH).

BKGVISU Visualisation of intermediate results (YES/NO).

BKGSTEP Step in pixels of the grid of background reference positions.

BKGPOL Degree of the bivariate polynomial for background fiting (method POLY).

BKGRAD Radius (radx, rady) in pixels of the window for local estimate of the background. The window is parallel to the orders (radx is measured along the orders, rady is parallel to the columns). (method SPLINE)

BKGDEG Degree of spline polynomials (method SPLINE).

BKGSMO Smoothing factor for smoothing spline interpolation. See Section  7.4 (method SPLINE).

EXTMTD (See definition in Table 7.7)

SLIT (See definition in Table 7.7)

OFFSET (See definition in Table 7.7)

SAMPLE Defines the wavelength step of the spectrum sampled in wavelengths. It can either be a real number indicating the step in units of Ångstrøm or a reference file corresponding to an image sampled in the space order-wavelength. 2|c| Parameters: FILTER command Description

BKGxxx All background parameters : see definitions above.

MEDFILT widx,widy,no_iter. See help of command FILTER/ECHELLE.

CRFILT radx,rady,mthresh.

CCDFILT read-out noise (in e-), inverse gain factor (e-/ADU), threshold (in units of standard deviation).

 

STD Raw Standard star, in STANDARD reduction mode.

RESPONSE Computed instrument response in STANDARD reduction. If the name NULL is assigned to this parameter no response correction is applied in the REDUCE command. Instead, the blaze function is fitted.

FLUXTAB Table with absolute fluxes for the Standard star, in STANDARD reduction mode. The tables are in the area MID_STANDARD

FILTMED Radius in x and y, threshold, as in command FILTER/MEDIAN used to smooth the response function.

FILTSMO Radius in x and y, threshold, as in command FILTER/SMOOTH used to smooth the response function.

PIXNUL Number of pixels to set to zero at the edges of each order.

BKGxxx All background parameters : see definitions in Table 7.8)

FFOPT Flat-Fielding option (YES/NO)

CORRECT Flat field correction image (required if FFOPT=YES).

BLAZE Smoothed flat field (required if FFOPT=YES).

EXTMTD (See definition in Table 7.7)

SLIT (See definition in Table 7.7)

OFFSET (See definition in Table 7.7)

SAMPLE (See definition in Table 7.7) 2|c| Parameters: REDUCE command Description

BKGxxx All background parameters : see definitions in Table 7.8)

FFOPT Flat-Fielding option (YES/NO)

CORRECT Flat field correction image (required if FFOPT=YES).

BLAZE Smoothed flat field (required if FFOPT=YES).

EXTMTD (See definition in Table 7.7)

SLIT (See definition in Table 7.7)

OFFSET (See definition in Table 7.7)

SAMPLE (See definition in Table 7.7)

RESPOPT Option for the response corection (YES/NO).

RESPMTD Method for the instrumental response correction (STD, IUE).

RESPONSE Name of the response image as produced by RESPONSE/ECHELLE (required if RESPMTD=STD).

RIPMTD Defines the ripple correction algorithm as SINC for the method fitting the blaze function, described by Ahmad(1981), and as OVER for the method using the overlapping region of the orders, proposed by Barker (1984) (required if RESPMTD=IUE).

RIPK Defines the initial guess for the parameter k in Equation 7.5. The default value is updated during the wavelength calibration.

ALPHA Defines the initial guess for the parameter in Equation 7.5.

MGOPT Merging option (YES/NO).

MRGMTD Merging method (AVERAGE, NOAPPEND).

DELTA Interval (in wavelength units) to be skipped at the edges of each order.