Standard 2 Light Curve Display
- Shows PCA counts/bin vs time in bins.
- The advantage of this display over std1 lightcurve display is that
this one will display different layers within the PCUs. Layer 1 shows most source flux particularly from soft sources. Only hard sources get much flux into the bottom layer 3. For weak sources the rates in layers 2 & 3 are almost all internal background events. This can be seen more easily if
all 4 layers are shown on the plot together. Layer 1 will show
faint sources better than the sum of all 3 layers.
- Another feature of the std 2 lightcurve is the "Adjust Channel Boundaries"
button that allows you to change the energy channels being used to display
the data. The current bin-to-energy conversion factor is: 1 channel = 0.38 keV, so selecting a bin range of 5 to 26 will approximately cover 2-10 keV.
NOTE: When the channel range is changed, the points already displayed are NOT rebinned! (They are not cleared, but they remain at the previous energy range.) Only the new data received is affected.
- An explanation of the timestamps.
Orientation:
- At the top is a bar of options controls.
- At the top center of the lightcurve is a status line showing important
options selected. If you save an ascii dump, these
options will be preserved in the output.
- Below the lightcurve the boxes show the count rate of the sum of all PCUs in each layer.
- At the lower right corner, pressing the yellow box marked 'Adjust Channel Boundaries' will launch a pop-up window in which you can change the energy channel range to be displayed.
Options buttons:
File:
- Freeze [to stop scrolling of data, select again to resume.]
- Save or E-mail File [Allows you to email an ascii dump
or postscript plot to yourself.
- Quit [quits the window.]
Select: [to choose what data is displayed in the lightcurve. Most of a source's flux is stopped in layer 1, especially for soft sources. Only hard sources get much flux in layer 3. For weak sources the rates in layers 2 and 3 are almost all internal background events.]
- Sum All Layers [default, this is like std 1 lightcurve]
- All Layer 1
- All Layer 2
- All Layer 3
- All 4 plots [useful to demonstrate why you want to look at layer 1]
Yaxis:
- Linear - zero min
- Log - zero min
- Linear - own Scale [adjustable limits]
- Log - own Scale [adjustable limits]
Statistics [chooses what units to show at the bottom of the window.]
- counts/sec [shows counts/sec]
- Total Counts [calculates total area under the curve in number of total counts regardless of binsize.]
Options [selects which bin size to use for time scaling. This display always contains 512 bins, so the resulting total time span is also shown below.] See warning about loss of data below!
- X1 (16s bins) [default] [8192 sec (=~ 2 h 17 min) total span]
- X2 (32s bins) [16384 sec (=~ 4.5 hours) total span]
- X4 (64s bins) [32768 sec (=~ 9 hours) total span]
WARNING! Selecting a new binning does NOT re-bin the data previously shown in the window! The data in the window will be cleared and the new binning will take effect on the next data received.
Display
- with Gaps [show SAAs and data gaps as gaps in the lightcurve, preserving the correct temporal spacing]
- without Gaps [all data is shown contiguously, including occult and slew data]
- Late Data [pops up a window when data is late]
- Strip Chart [shows late data graphically]
- Clear LC [erases the data in the display]
XTE SOF - xtesof@xtesof.nascom.nasa.gov
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