Finding the Line Shift

Using line scan data we can find line centres using the plotter program. Soupcal files are stored in the relevant camera directory (on store1) along with the image data. On any of the control machines do the following (as obs):

1. cd ~/SSTJavaTools
   
2. ./plotter /data/store1/KVA/camXX (example location)
   

   Figure 2: Plotter Program

   

3. Use the file tree on the left to load a SOUP calibration (.fz) file. An example filename would be
   soupcal.6303.20060613.14:22.fz.

4. If the plot does not resemble a spectral absorption or emission feature on an uneven background, then go no further and try different data.

5. If there are any large intensity drops on the plot, remove them by selecting with the left-mouse button then using the scissor icon. This will improve the line fit.

6. By dragging with the left-hand mouse button, select a wavelength range that approximately covers the spectral feature.

7. Using the toolbar button, perform a Gaussian fit. If successful, a line centre should now be obtained, and labelled on the plot.

8. Record the line shift and repeat from 3 for other data. The arrow toolbar buttons can be used to switch between different plots.

Now you have found all your line centres you are ready to make changes to your SOUP sequence file. Please note that the plotter program will give you a line centre as a floating point number whereas only integers can be used in the sequence file.