Identify the lines in one of the rows of the spectrum

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Identify the lines in one of the rows of the spectrum

Different parameters are used, indicated in the following fields of the Main window:

the name of the table with the wavelengths of the comparison lines, indicated in the field Line Catalog.
the range in wavelengths to be considered, indicated in Wavelength Range
the Minimal Intensity in Catalog is used to perform a selection of the brightest lines of the catalog
and the Calibration Starting Row will be used for the lines identifications. If this parameter is set to its default value 0, the central row will be considered.

After setting these parameters, click the $\fbox{\tt Identify...}$ button. to pop up the Identify window. The menu $\fbox{\tt Utils}$ in the menu bar provides graphic related commands. The identification starts by clicking on $\fbox{\tt begin}$ , which plots one row of the spectrum in the graphic window, indicates the position of the detected arc lines with blue vertical traces and gives a cursor.

When a detected line is clicked on, the interface expects the corresponding wavelength to be clicked in the wavelength list. The identified line turns green and an identification message appears in the MIDAS monitor. It is then possible to identify a new line. When a sufficient number of identifications has been performed, clicking with the middle mouse button in the graphic window desactivates the cursor. The full spectrum is plotted by default. Clicking again on $\fbox{\tt begin}$ deletes all identification, while more identification can be added by clicking on $\fbox{\tt continue}$ . Identifications can also be removed one by one with the button $\fbox{\tt delete}$ .

The x-axis and y-axis limits of the plot can be modified interactively with the menu $\fbox{\tt Frame}$ . The Begin button sets the x-axis to default values in order to start each time from a predictible configuration. The Continue button however will take the defined limits. The procedure to ideintify lines in zoomed areas of the spectrum is therefore:

start with Begin
if you identified no line, simply exit with the middle button of the mouse
select new limits in x and y.
make more identifications with Continue

**Figure G.4:** Lines Identification Window

Next: Wavelength calibration Up: Getting Started Previous: Detecting lines in the

Petra Nass
1999-06-15