As an example of the use of the commands described above, we here include the tutorial procedure, executed as TUTORIAL/LONG.
The input images are wlc, the wavelength calibration frame, and obj, the object. The catalogue of laboratory wavelengths used is stored in the table lincat.
INIT/LONG
GRAPH/LONG
MAKE/DISPLAY
!
WRITE/OUT Copy test images
-DELETE lndemo_*.*
-COPY MID_TEST:emhear.bdf lndemo_wlch.bdf
-COPY MID_TEST:emth.bdf lndemo_wlcth.bdf
-COPY MID_TEST:emstd.bdf lndemo_wstd.bdf
-COPY MID_TEST:emmi0042.bdf lndemo_bias1.bdf
-COPY MID_TEST:emmi0043.bdf lndemo_bias2.bdf
-COPY MID_TEST:emmi0044.bdf lndemo_bias3.bdf
-COPY MID_TEST:emmi0045.bdf lndemo_bias4.bdf
-COPY MID_TEST:emmi0046.bdf lndemo_flat1.bdf
-COPY MID_TEST:emmi0047.bdf lndemo_flat2.bdf
-COPY MID_TEST:emmi0048.bdf lndemo_flat3.bdf
-COPY MID_TEST:emmi0049.bdf lndemo_flat4.bdf
-COPY MID_TEST:thorium.tbl lndemo_thorium.tbl
-COPY MID_TEST:hear.tbl lndemo_hear.tbl
-COPY MID_TEST:l745.tbl lndemo_l745.tbl
-COPY MID_TEST:atmoexan.tbl lndemo_atmo.tbl
!
WRITE/OUT "This tutorial shows how to calibrate long slit spectra"
WRITE/OUT "The package assumes wavelengths increasing from"
WRITE/OUT "left to rigth."
WRITE/OUT "It is assumed that the images have been already"
WRITE/OUT "rotated, corrected for pixel to pixel variation"
WRITE/OUT "and the dark current has been subtracted."
WRITE/OUT "Input data are:"
WRITE/OUT "wlc.bdf - wavelength calibration image"
WRITE/OUT "obj.bdf - object image"
WRITE/OUT "lincat.tbl - line catalogue"
!
WRITE/OUT "Combining flat and dark images"
!
LOAD lndemo_flat1
CREATE/ICAT bias lndemo_bias*.bdf
COMBINE/LONG bias lnbias MEDIAN
STAT/IMA lnbias
!
CREATE/ICAT flat lndemo_flat*.bdf
SET/LONG TRIM=20,60,520,457
PREPARE/LONG flat.cat lndemo_ft
CREATE/ICAT flat lndemo_ft*.bdf
COMBINE/LONG flat lnff AVERAGE
NORMALIZE/FLAT lnff lnflat 190.
!
CREATE/ICAT lndemocat lndemo_w*.bdf
READ/ICAT lndemocat
LOAD lndemo_wlch
WRITE/OUT "Extracting useful part of spectra with command PREPARE/LONG"
SET/LONG TRIM = 0,60,0,457
PREPARE/LONG lndemocat.cat lndemo
!
WLC:
SET/GRAPH PMODE=1 XAXIS=AUTO YAXIS=AUTO
SET/LONG WLC=lndemo1 LINCAT=lndemo_hear YWIDTH=10 THRES=30.
SET/LONG YSTEP=10 WIDTH=8 TWODOPT=YES DCX=2,1
!
SESSDISP = "NO "
SHOW/LONG wlc
!
WRITE/OUT Search lines:
WRITE/DESCR {WLC} STEP/D/2/1 -2.
SEARCH/LONG ! search calibration lines
PLOT/SEARCH
!
WRITE/OUT "Identify some of the brightest lines:"
WRITE/OUT
WRITE/OUT " X = 379.30 922.50 "
WRITE/OUT " WAV = 5015.680 5606.733"
WAIT 2
IDENTIFY/LONG ! interactive line identification
SET/LONG WLCMTD=IDENT TOL=0.3
CALIBRATE/TWICE ! wavelength calibration
PLOT/IDENT ! display initial identifications
!
WRITE/OUT Compute the dispersion coefficients by fitting a 2-D polynomial
WRITE/OUT to the whole array
PLOT/CALIBRATE ! display all identifications
PLOT/RESIDUAL
PLOT/DISTORTION 5015.680
!
SAVE/LONG ses1
WRITE/OUT "Now calibrating another arc spectrum in GUESS mode"
SET/LONG WLCMTD=GUESS GUESS=ses1 WLC=lndemo2 LINCAT=lndemo_thorium
SET/LONG WIDTH=4 THRES=3. TOL=0.1 ALPHA=0.2
LOAD {wlc}
SEARCH/LONG
CALIBRATE/LONG
!
WRITE/OUT "Now demonstrating the three possible ways to apply the"
WRITE/OUT "dispersion relation : "
WRITE/OUT " - APPLY/DISPERSION involves no rebinning and outputs a table."
WRITE/OUT " Input must be a 1D spectrum or a row of a long-slit spectrum"
WRITE/OUT " - REBIN/LONG rebins row by row, taking coefficients from coerbr.tbl"
WRITE/OUT " - RECTIFY/LONG applies the 2D polynomial dispersion relation"
WRITE/OUT "Note: Rebin can be applied before or after extraction"
!
!INIT/LONG ses1
!
APPLY/DISPERSION {wlc} wlct @100
PLOT/SPECTRUM wlct
!
REBIN/LONG {wlc} wlcrb
LOAD wlcrb
PLOT wlcrb @100
!
RECTIFY/LONG {wlc} wlc2
LOAD wlc2
PLOT wlc2 @100
!
WRITE/OUT "Session is now saved, initialized, and loaded from session tables"
SAVE/LONG mysess
INIT/LONG
SESSDISP = "NO "
SHOW/LONG
INIT/LONG mysess
SESSDISP = "NO "
SHOW/LONG
!
WRITE/OUT "Now extracting a spectrum with two possible methods:"
WRITE/OUT " - Simple rows average with EXTRACT/AVERAGE"
WRITE/OUT " - Optimal extraction with EXTRACT/LONG"
LOAD/IMA lndemo3
SET/LONG REBSTR=4600. REBEND=5800. REBSTP=2.00
REBIN/LONG lndemo3 ext8
SET/LONG LOWSKY = 189,198 UPPSKY = 204,215
SET/LONG GAIN=2. RON=5. THRES=3. RADIUS=2
SKYFIT/LONG ext8 stdsky
LOAD stdsky
COMPUTE/IMAGE ext7 = ext8 - stdsky
SET/LONG OBJECT = 199,203
EXTRACT/AVERAGE ext7 stda
PLOT stda
EXTRACT/LONG ext8 stde stdsky
PLOT stde
!
WRITE/OUT "Now computing instrumental response"
!
SET/LONG FLUXTAB=lndemo_l745 EXTAB=lndemo_atmo
PLOT/FLUX
EXTINCTION/LONG stde stdext
RESPONSE/FILTER stdext
INTEGRATE/LONG stdext
RESPONSE/LONG fit=SPLINE
PLOT/RESPONSE
CALIBRATE/FLUX stdext stdcor
CUTS stdcor 100.,500.
PLOT stdcor