This tool shows an energy spectrogram. The time period of the data shown is determined by the user selected time period in the main window (either the red vertical bars or the text entry boxes).
On startup, there is no spectrogram shown. This is because it can take a long time to load all the data needed for the spectrogram, and the default spectrogram may not be the one in which you are interested. So the program lets you choose the spectrogram to display. Just pick the desired spectrogram by name in the pulldown menu labeled \"Selected Spectrogram\". Note that after you select a spectrogram, you must click the \"Apply\" button in order to display the spectrogram.
The spectrogram is constructed in the following way: The energy spectra for all the channels associated with this spectrogram are accumulated for a certain amount of time. This time bin width is settable using the entry box on the top left of the spectrogram window. Using the spectrum averaged over the time bin width, the flux values at N evenly spaced points along this spectrum are obtained using interpolation. The interpolation is done in a logarithmic scale, i.e., its a linear interpolation of the logarithms of the flux for each channel. The energy midpoint of the channel is taken at the geometric mean of the low and high energies.
You can change the number of interpolated points using the entry box labelled \"Num Energy Bins\" at the top right of the spectrogram window.
As with the spectrogram selection, you must click the \"Apply\" button in order for your changes in the time bin width or the number of energy bins to take effect.