The detection of arc lines in the wavelength calibration frame .bdf (wlc) for all slitlets selected in .tbl (mos) is done by
Midas ...> SEARCH/MOS
This command will take the slitlets' limits from .tbl and the eventual stepping and binning factor from (3,3). In all CCD rows of .bdf that are selected by these parameters it will look for intensities above the chosen threshold when comparing to the median intensity over a chosen window (threshold and window are defined by (200,5)). Any lines detected this way will be centered by (GRAVITY) and stored in .tbl (linpos).
|:X||x-position of line (world coordinates)|
|:Y||y-position of line (world coordinates)|
|:PEAK||maximum intensity of line|
|:SLIT||number of slitlet|
Midas ...> LINPLOT/MOS
you will get a plot of the x-positions of all found arc lines versus the CCD rows. With
Midas ...> LINPLOT/MOS 1 3
you will get a plot of the first CCD row of slitlet 3 for which line positions are stored in .tbl. The detected lines are marked in the plot.
If you do not know the central wavelength and mean dispersion of the grism you used you have to identify at least two arc lines in any row of any slitlet.
Midas ...> IDENTIFY/MOS
The row, in which the lines shall be identified, is read from (0). If you do not provide any number either there or on the command line, the program will take the first CCD row that has been scanned. As frame it will use .bdf.