Use EXTRACT/MOS to sky-subtract and extract the detected objects in an output frame with an optimum extraction scheme using different weights for the individual rows (following Horne, 1986, PASP 98, 609). The procedure is iterative. If the number of iterations is set to a negative number, a spectrum computed with equal weights is returned. The sky frame ( (sky)) and the CCD read-out-noise and gain ( ) are used to compute the errors of the resulting spectra. The extracted spectra are stored in a 2-D frame, each line corresponding to one extracted object. In addition, the errors for the extracted spectra are stored in this frame, one line per spectrum.
To rebin the resulting frames to constant wavelength steps use:
Midas ...> SET/MOS extobjec=in
Midas ...> SET/MOS rebstrt=start rebend=end rebstp=step
Midas ...> REB1D/MOS ? reb
This will split the extracted frame in.bdf into individual frames with constant wavelength steps, named reb0001, reb0002, etc. using the dispersion coefficients of .tbl.
If you want to avoid rebinning noise you can use APPLY/MOS to produce a table with the columns :WAVELENGTH, :FLUX, :FLUX_ERROR, and :BIN.
Midas ...> SET/MOS extobjec=in calobjec=ap
Midas ...> APPLY/MOS
This will take the frame in.bdf and convert it to tables ap0001.tbl, ap0002.tbl, etc. using the dispersion coefficients of .tbl.
=31 =03 =1999