The user can use the mouse to select a file from the directory listing,
or move around the directory structure. The file suffix filter is normally
set by CASPER to filter the type of file it is expecting.
If creating a new file, the user may type the name into the selection
box. CASPER will automatically add the current directory path to the name,
and in many cases will append the correct suffix for the expected file
type.
Printer information is obtained from the printers.dat file, [in $CASPER_DAT],
which should be configured for the user's CASPER installation. The widget
allows the operator to select landscape or portrait orientation for the
plot, the number of copies to be created, and which of the available printers
the plot should be sent to.When the set-up is complete, pressing the DONE
button will make the options available for that session. HELP will create
a window with some helpful text about this window.
The Preferences Widget is used to define the colors that CASPER uses
when plotting to the screen (color PS plots are not currently supported)
and other graphics related parameters.
The Preferences widget consists of six sections: A row of control
buttons across the top; a plot object selection panel in the middle; the
RGB sliders
below that; and controls for character sizes, the animation frame limit,
and aberration correction at the bottom.
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Done: Destroys the Color Setup widget.
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Save: Saves the current color setup to the user's personal CASPER
space. This color setup will be restored as the default at the beginning
of the next CASPER session.
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Load: Loads the previously saved user color setup.
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System Defaults: Restores the system default color setup which
should look reasonable on most systems.
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Help: Provides a description of the operation of this widget.
There are a number of individual plot items in the Target plot, each of
which has its own associated color which can be altered using this widget.
The user selects the plot object they wish from the droplist widget, and
the small colored area will change to match the current color of that plot
item. This color can be changed via the RGB sliders.
The RGB sliders allow the user to change the rd, green and blue components
of the color of the currently selected plot object. As the sliders are
moved, the small colored area next to the plot object selection droplist
will change to match the new RGB values. In addition, if the plot object
exists on the current Target plot, then the user can observe the effect
of the color changes upon this object in real time.
Plot Character size controls the size of some characters displayed on the
plot. Postscript character size controls the size of some characters on
Postscript printouts. These generally need to have a smaller valu than
the plot character size to look good on a printout.
This parameter sets the maximum number of animation frames allowed.
It depends upon the speed of the machine on which CASPER is running.
Faster machines allow for more frames to be displayed during an animation.
This parameter indicates the aberration corrections to be applied to
determine the state of the target body. The string may be in upper, lower,
or mixed case; and it can be one of the following options:
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NONE - Apply no correction. Return the true state of the target
body relative to the observer.
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LT - Correct for planetary (light time) aberrations.
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LT+S - Correct for planetary (light time) and stellar
aberrations.
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CN - Converged Newtonian light time corrections. This is the same
as LT corrections but with further iterations to a converged Newtonian
light time solution. Given that relativistic effects may be as large as
the higher accuracy achieved by this computation, this correction is
seldom worth the additional computations required unless the user
incorporates additional relativistic corrections.
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CN+S - Converged Newtonian light time corrections and stellar
aberration.
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This tool is used to show information about SP kernels that are available
for use by CASPER. Each SP kernel is broken up into various segments,
each one describing the position of a "Target" body with respect to a "Center"
body, such as the Cassini spacecraft with respect to Jupiter's barycenter
in the example above. Each segment also covers a specified time period,
also indicated. In the above example, information about the position
of Cassini relative to Jupiter prior to 2000 November 9, 15:17:03.847 (UTC)
is not available. If a request were made for a plot at some prior
time, and no other SP kernel was loaded that covered that time period,
CASPER will issue an error message.
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The slider at the bottom allows you to scroll through the various segments
within each SP kernel.
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To load an SP kernel, select the type by clicking on either the Load
Tour Kernel or Load Ephemeris Kernel buttons. The former
will start searching for files in CASPER's directory for tour (spacecraft)
kernel files. Ephemeris kernel files refer to all those that describe
solar system objects, such as planets, satellites, asteroids, and the Sun.
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Click on Done to close the widget.
This error message may be displayed if you have not loaded enough SP kernel
data to satisfy the combination of plot time, target body, and observer
that you have requested.
This widget allows the user to specify the rest of the module parameters.
These include the turn and acceleration rates for flyback and reposition
slews in the x-, y-, and z-directions (depending on the type of module);
the peak coast and acceleration rates for start-stop scans (again,
directions available depend on the type of module selected); whether the
module will be flyback or reposition; the number of scans and the number
of footprints per scan the s/c will perform; and the pause duration for
every footprint. The status window will display error messages if input
values are out of range.
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Buttons
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Fly/Repo: Allows user to input turn and acceleration rates for
flyback and reposition slews, where the directions available depend upon
the type of module selected.
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Scan: Allows user to input the peak coast and acceleartions rates
for start-stop scans, where the directions available depend upon
the type of module selected.
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More: Allows user to input whether the module will be flyback or
reposition, the number of scans and the number of footprints per scan, and
the pause duration for every footprint depending on the type of
module selected.
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Defaults: Resets all values to the default rates and
accelerations.
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Use: Minimizes the widget and uses the entered parameters.
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Cancel: Closes the widget and disregards any changes made
here.