5.3 Data Management

The three data management menus control data display, file manipulation (e.g. writing to tape, deleting files, etc.), and whether or not TCS information is stored in the file header. Samples of the four data management menus can be found in Figures 5.9, 5.12, 5.14, and 5.15.

5.3.1 Look

The three entries in this menu are the same as in the Scans menu. If Show Interferogram is selected, the raw intererogram of the specified file is displayed in a window on the screen. An example is shown in Figure 5.10. If the Show Spectra option is selected then a power spectrum of the interferogram will be calculated and displayed as illustrated in Figure 5.11. All plotting is performed with the Grapher Tool, details of which can be found in the CFHT document ``A User's Manual For the CCD Data Acquisition User Interface,''@ by John Kerr and Olivier Le Fèvre. Archive numbers can be specified to plot earlier data and the two keywords `current.fits' and `previous.fits' provide short cuts for plotting data for the most recently completed scan and the previous scan.

5.3.2 Eng

This menu, shown in Figure 5.12, is used primarily for engineering and setup purposes. The names of two interferograms to be plotted with grapher can be specified in the boxes for File1 and File2. The difference between the two can also be illustrated by selecting the Show Difference option from the menu. The Eng menu enables the user to confirm that after a pair of scans the carriage has returned to its starting position, since any missing points in one of the scans will produce an obvious shift in the forward and reverse interferograms near ZPD. It also provides a convenient way to inspect the complete content of the interferogram just recorded, and to compare observations from one scan to the next if the intensity has not changed. A sample plot of a portion of an interferogram near ZPD is illustrated in Figure 5.13.

5.3.3 Files

The data are recorded in `fits' format, and each file is assigned a name consisting of a 5 digit number (the `odometer' reading), followed by the letter `o' and the extension `.fits'. The exposure name is displayed on the FTS Status icon which appears whenever a scan is in progress (figure 5.4). The name of each exposure should be recorded on an FTS Log sheet (see Appendix D) for future reference.

The `Files' menu controls all file operations and, for the purposes of discussion, can be divided into two parts: `What to do', and `what files to do it to'.

There are four operations which can be performed on the files. They are:

The second part of the menu specifies which files are to be displayed, saved, etc. There are four entries:

One can select specific subgroups of files, based on there file type (in almost all FTS applications this is `o', for object) or their odometer reading, which is the numerical part of the file name. These can be entered in the File Type Override, and Range Override entries.

A word of caution: Before writing a large number of files to tape or, even worse, deleting them from your disk space, it is a good idea to first list them with the List FITS files option to confirm that the correct files have been identified.

5.3.4 Modes

This menu (Figure 5.15) specifies whether or not the data will be displayed automatically.

The two entries on this menu are:

Please send comments and suggestions to: veillet@cfht.hawaii.edu