Parameters

For the storage of control parameters and results, the context LONG uses a number of special keywords. They are intialised by the command SET/CONTEXT LONG, their values can at any time be listed by typing SHOW/LONG. The following table provides a brief description of the purpose of the LONG keywords:

 

Table 6.7: Keywords Used in Context LONG

Parameter	Description
ALPHA	Rejection parameter for lines matching [0,0.5]
AVDISP	Average dispersion per pixel
BETA	Non-linearity in mode LINEAR
BIAS	Bias image or constant
BIASOPT	Bias Correction (YES/NO)
COERBR	Table of coefficients for RBR
COMET	Combination method (AVERAGE/MEDIAN)
COORFIL	Name of coords table of GCOORD/LONG
COROPT	Computes correlation
CORVISU	Plots correlation peak
DARK	Dark image or constant
DARKOPT	Dark Correction (YES/NO)
DCX	fit degree of the dispersion coeff.
DISPCOE	Dispersion coefficients
EXTAB	Extinction Table
EXTMTD	Extraction method (AVERAGE, LINEAR)
EXTOPT	Extinction Correction Option (YES/NO)
FDEG	Flat fitting degree
FFIT	Flat fitted function
FILTMED	Radius of median filter
FILTSMO	Radius of smoothing filter
FITD	Degree of fit
FITD	fit degree of the dispersion coeff.
FITYP	Type of fit (POLY, SPLINE)
FLAT	Flat-Field Image
FLATOPT	Flat Correction (YES/NO)
FLUXTAB	Flux Table of the standard star
FVISU	Visualisation flag (YES/NO)
GAIN	Gain (e-/ADU)
GUESS	Guess session name
IMIN	lower limit from LINCAT
INPNUMB	Input generic name
INPUTF	Input generic name
INSTRUME	instrument
LINCAT	line catalogue
LINTAB	Table of line identifications
LOWSKY	Lower, upper row number of lower sky
MAXDEV	Maximum deviation (pixels)
NITER	Number of iterations
NPIX	size of the raw images in pixels
OBJECT	Lower, upper row number of object spectrum
ORDER	Order for optimal extraction

 

Table 6.8: Keywords Used in Context LONG (continued)

Parameter	Description
OUTNUMB	Output starting number
OUTPUTF	Output generic name
PLOTYP	Type of plot (RATIO, MAGNITUDE)
RADIUS	Radius for cosmics rejection
REBEND	Final wavelength for rebinning
REBMTD	Rebinning method (LINEAR, QUADRATIC, SPLINE)
REBOPT	Rebin Option (YES/NO)
REBSTP	Wavelength step for rebinning
REBSTRT	Starting wavelength for rebinning
RESPLOT	Plot flag for response computation
RESPONSE	Response Image
RESPOPT	Response Correction Option (YES/NO)
RESPTAB	Intermediate Response Table
RON	Read-Out-Noise (ADU)
ROTOPT	Rotation Option (YES/NO)
ROTSTART	Y-start after rotation
ROTSTEP	Y-step after rotation
SEAMTD	Search centering method (GAUSS, GRAV, MAXI)
SESSION	Session name
SHIFT	Shift in pixels
SIGMA	Threshold for rejection of cosmics (std dev.)
SKYMOD	Mode of fitting
SKYORD	Orderfor sky fit
SMOOTH	Smoothing factor for spline fitting
START	start points of the raw image.
STD	Standard Star Spectrum
STEP	start points of the raw image.
THRES	Threshold for line detection (above local median)
TOL	tolerance in Angstroms for wavelength ident.
TRIM	Trim window (x1,y1,x2,y2) in pixels
TRIMOPT	Trim Option (YES/NO)
TWODOPT	Computes bivariate polynomial option.
UPPSKY	Lower, upper row number of upper sky
WCENTER	Central wavelength
WIDTH	Window size in X for line detection (pixels)
WLC	wavelength calibration image
WLCMTD	Wavelength calibration method (IDENT,GUESS)
WLCNITER	Minimum, Maximum number of iterations
WRANG	wavelength range to take from LINCAT
YSTART	Starting row for the calibration (pixel value)
YSTEP	Step in Y for line searching (pixels)
YWIDTH	Window size in Y for line detection (pixels)