ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

90 CHAPTER 12. DATA SLICING
We suggest you use all the variables at least once during your first slicing: it will greatly
help you to understand how ISOCAM operates.
After some time, you will discover that some variables are not useful to you, and that you
can leave them aside, if you remember how you programmed your observations. For example, if
you are working on a raster, you won’t need the Beam Switching Flag. As a matter of fact, there
is only one detector offset per detector gain, therefore the offset is useless. Some other variables
may look useless to you, but may be indeed of some interest, especially if you are working on
data from the PV phase.
For this particular first slicing, don’t use the enhanced OTF in case of telemetry drops. More
will be told about this in Section 19.
12.3.4 Run the slicer
The next step is to click on the ‘SLICE’ button. The Slicer will run on the data you have
selected, according to the variables you have selected. Let’s see what this means.
The slicer will read your file (the CIER.FIT you have selected), and flag each record where
the value of one of the selected variables has changed. It will propose to build a new SCD each
time such an event happens. Of course, you don’t want to produce all these SCDs, because
some of them will be made of frames taken while the camera is adjusting its configuration for
the observation that you have requested. One other point is that some observations have been
made with different configurations in a single AOT: for example you will find in the same file
the same raster on the same sky position done in two different filters. If they are put in the
same file, it does not mean that they should be assigned to the same SSCD. All these data
manipulations are done on the x handle slice window that appears in front of you.
12.3.5 The x handle slice window.
Figure 12.2 shows the x handle slice window. It is divided in two parts, each of them is divided
in two parts too. Let’s go through them.
The top of the window presents the results of the slicing process. On the left, a large table
gives you the values of the variables you choose for each SCDs that the x slicer has found
(remember that the slicer creates a new SCD each time one of the variables changes). The titles
on the top have been shortened, so Table 12.1 presents the conversion.
On the right of this table are two columns of buttons, named SCD # and Merge SCD
where # stands for the number of the SCD. Note that by default, all SCDs are selected, and
none are merged together. There are scroll bars that allow you to align the row containing the
informations about the SCD Number # and the corresponding buttons.
The bottom of the x handle slice window is made of a set of buttons on the left and a
pull-down menu named ‘Advanced Slicing’ on the right.
The functions of the buttons are:
• Redisplay: Redisplay the x handle slice window, showing only the selected SCDs. Note
that you must redisplay before slicing.
• Continue: When satisfied with the slicing, go into the SSCD, SCD and eventually DSD
creation. . .
• Unselect All SCDs: self explanatory.