The Tracking Error Graph is a graphical presentation of the most recent 15 minutes of guiding errors. You can choose to display the errors in either or both axes, with or without RMS trend lines, and expressed in either the camera (X–Y) or telescope (RA–Dec) frame of reference. The graph is scrolled toward the left automatically when the right edge is reached. The vertical scale and time duration of the graph are selectable. The peak excursion and current RMS value of each error are displayed at the bottom of the graph for quick reference.
The Tracking Error Graph window can be adjusted to any desired size using the mouse; the graph automatically stretches or shrinks to fill it.
Tracking errors are always collected whether this window is active or not, so you can turn it on to check for guiding anomalies if you suspect one has occurred based on inspection of a main camera image.
Please note that the graph shows the instantaneous measurements of guider offset, not the actual tracking of the mount itself. If you set the Aggressiveness to a low value, such as 2 to 4, the mount will effectively be following a “rolling average” of the current and recent guider measurements. In that situation, you may see a large scatter on the graph due to seeing, but the actual guiding performance could be several times better than indicated by that scatter. Of course this only works if the “real” errors are slow enough to be tracked out with a low aggressiveness.
All options are selected from the menu 
at the bottom left corner of the window.
The Plot submenu
contains commands to select what is plotted. Choose Camera
Axes or Telescope Axes
depending on whether you want to see the guiding errors as measured in
the camera frame of reference, or as rotated to the telescope frame. The
latter setting can be useful when determining if poor guiding results
from a mechanical problem in the telescope mount.
Please note that the default
setting of Telescope Axes means
the graph display will likely not
match the error display on the Guide
tab. This is normal, and is more informative than displaying camera
coordinates because the autoguider camera may be rotated relative to the
telescope mount axes.
Select X Error to display only the error in the X axis, Y Error for that in Y, X and Y Errors for both to be superimposed on one graph, or X and Y (separate) to display them in separate graphs within the same window, as in the example shown above. X errors are always plotted in dark green and Y errors in dark blue.
Select Show RMS Trends to display the root-mean-square error as well as the instantaneous error. The RMS error is a moving average based on the measurements made over an adjustable interval called the RMS Window, discussed below. RMS Trends are not available when X and Y Errors are plotted on the same graph. They are shown in a lighter color than the raw measurements.
The graph can be plotted with symbols at each sample: small triangles for raw error measurements and plus signs for RMS averages. Alternatively, you can request that Lines joining points of the same type instead, which is easier to see if the graph window is not very big. Intervals when guiding is inactive or the guide star was lost are indicated by breaks in the line.
The Vertical Scale submenu allows you to select the Y axis range. The available scales are ±0.5, ±1, ±2, ±5, ±10, and ±20 pixels. You cannot display tracking error plots in arc-seconds.
The Time Span submenu allows you to select how much data is plotted in the graph, based on a time range ending at or near the time of the most recent measurement. The available choices are 1, 3, 6, 10, and 15 minutes. Data is not lost when the selected Time Span is shortened, only when the data point ages beyond the maximum limit of 15 minutes.
The RMS Window submenu allows you to specify the length of time over which data is averaged when computing the RMS error. You can choose between 30 seconds, 1, 2, 3 or 4 minutes. RMS information is not plotted for a measurement if there is insufficient data in the interval of this duration immediately preceding it.
Plot type, Vertical Scale, Time Span, and RMS Window length can be adjusted at any time and the display is automatically updated.
The Peak Values submenu allows you to specify whether the extrema displayed in the status area at the bottom of the graph Reset Automatically, as soon as the peak data point is no longer displayable, i.e., is 15 or more minutes older than the most recent point, or are Reset Manually, on user command. When in manual reset mode, use the Reset Now command to reset the peak display to zero. As new measurements are made, the peak values will creep upwards.
Click Save Data to record the available measurements to a disk file. This calls up a file selector dialog with which you navigate to the desired destination folder and specify a filename. The file is written in the same format as the Tracking Log.
Click Load Data to load and display a previously saved graph or a Tracking Log. (Tracking Logs exceeding 15 minutes in duration are automatically clipped. If necessary, you can divide them into shorter segments with any text editor.) If you start the guider after loading a file, old data will be automatically flushed as soon as the first measurement is made.
The Alarms display calls up the Tracking Error Alarms window. This is an alternative to using the Tracking Error Alarms command in the Options menu of the Guide Tab.
The Clear Graph command erases all data from the graph. If the guider is active, the next measurement made will begin a new graph, resetting the reference time shown in the window title to the current time.