This tool plots an energy spectrum as a function of time. You can choose which spectrum to display from a pulldown menu of possible spectra. Flux values for the spectrum are obtained over a specifiable time interval. In other words, the flux values for each channel in the spectrum are averaged over the time width you specify, and then the spectrum is constructed from these average flux values.
This time width is like a window which can slide over the larger time interval, creating a movie-like effect for watching flux changes as a function of time. Note that the boundaries of the larger time interval are defined by the time interval which you specified on the summary plot (either from the sliding red bars, or from the manually entered time range) before the opening of the Spectrum Plotter window.
Control over the display of the spectrum \"movie\" is done using a slider and also a set of VCR-like buttons. Both of these controls are just below the actual plot. The slider allows you to manually move the sliding time window, while the buttons allow automatic scrolling of the time window.
At the bottom of the spectrum plot, red boxes are drawn to indicate the energy boundaries of the channels whose flux points appear in the plot. Note that if a red box appears with no flux point above it, this indicates that the flux in that energy channel was zero for the curent measurement interval. The zero flux point cannot be plotted directly since the flux axis (the y-axis) uses a logarithmic scale. Thus the red boxes make it possible to distinguish time intervals when the flux is really zero from those time intervals where no flux measurement was made.
You can turn off the drawing of the red boxes using a checkbox available under the Settings menu.
Notice that the plot is auto-scaled according to the spectrum over the entire time range -- the scale stays the same as you drag the sliding window across the entire time range. This allows you to easily see relative changes in the flux, which would be difficult to do if the vertical scale kept changing.
You can save the currently displayed data, either as a PostScript plot, or as ascii data using the buttons at the very bottom of the window.