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.
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.
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.
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:
- List FITS Files:
Lists the names of all specified files.
- List FITS Headers:
Displays the complete FITS header for all of the
specified files.
- Write FITS Files to Tape:
Saves the specified files to tape.
When this option is selected you must also select the kind of tape you are using (CFHT currently supports Exabyte and DAT tape formats) as well as the tape
file format you desire.
Writing a tape in TAR format is much more efficient and much faster than
writing the files as individual FITS format files.
- Remove FITS Files:
Deletes the specified files from disk. It is important
to note that the files are not physically deleted from the summit disk
until after a copy has been sent to Waimea for archiving on the
optical
disk system. However, once `removed' the files can no longer be accessed
by the observer.
The second part of the menu specifies which files are to be displayed,
saved, etc. There are four entries:
- One File:
In this case the name of the file can be entered in the window
next to this entry. By entering `current.fits' (the default) the most
recent fits file is acted upon.
- All Files:
In this case all files on the disk are acted upon (within the
file type and range overrides discussed below).
- Already on Tape:
In this case all files which have already been written
to tape are acted upon, within the specified overrides (see below).
- Not on Tape:
In this case all files not written to tape are acted
upon, within the specified overrides (see below).
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.
This menu (Figure 5.15) specifies whether or not the data will be displayed automatically.
The two entries on this menu are:
- Display Image:
This selection is not applicable to conventional FTS observations.
- Display Graph:
If automatic is selected then the interferogram and/or spectrum
will be output on the screen automatically during each scan. If manual
is
selected then the user must ask for each plot to be displayed.
