The target tool is the primary tool in CASPER for visualizing and planning Optical Remote Sensing observations.  The target tool includes a number of options that allow you to control the appearance of your display, as well as design different types of observations.  Once you have started a session, the Target tool will display a plot of the target body from the observer at the specified time.
Image of Target Tool

The Target tool widget has four areas:

At the top of the screen is the menu bar containing the following menus:
  • The Sequence Design menu contains three sub-menus:
    • This sub-menu contains items that allow you to create mosaiced observation sequences using pre-defined Modules and Templates. The FOV Tools sub-menu contains items that allow you to associate one or more instrument field of views with the sequenced pointings that you have previously designed. A pointing is not visible on screen until a FOV is turned on.

    It also contains tools to examine the characteristics of a FOV in more detail.



    return to "Viewing a C Kernel."


  •  Animation Menu
  • Graphic Menu

    • The items within this menu allow the user to select which objects should be present on the main CASPER plot.
    1. Background Grid: This switches the background grid on or off. An ON/OFF flag indicates its current setting.
    2. Pointing Position: This will switch the plotting of markers that show the position of the boresight pointings for any modules that are currently plotted.. An ON/OFF flag indicates its current setting.
    3. Satellites: This switches the plotting of satellite position symbols on or off. An ON/OFF flag indicates its current setting.
    4. Sun: This switches the plotting of the Sun's position on or off. An ON/OFF flag indicates its current setting.
    5. Earth: This switches the plotting of the Earth's position on or off. An ON/OFF flag indicates its current setting.
    6. Orbits: This switches the plotting of the orbit paths of the satellites on or off. An ON/OFF flag indicates its current setting.
    7. Features: This switches plotting of the target body's features on or off. An ON/OFF flag indicates its current setting. A feature detail file needs to be available for the target body otherwise CASPER will report a missing file error. At present, only a feature file for the Earth is available.
    8. Image: This allow the user to select an image file for the target body to be displayed in the target window. Image files provided with CASPER are from the USGS database from voyager images. This option severly slows graphic updates in CASPER.
    9. Exobase: This switches plotting of an extra circle around the target body on or off. An ON/OFF flag will indicate its current setting. This circle can be used to represent exobase altitudes. The altitude information must be present in the features.tpc text kernel file located in the $SPICE_DIR directory.
    10. Stars: This switches plotting of stars on or off. An ON/OFF flag will indicate its current setting. The stars are represented by a + sign on the plot, with the size of the symbol representing the magnitude of the star. Two related items may be found under the Utilities menu, for limiting the number of stars that are plotted using magnitude (STAR LIMITS) and for identifying and retrieving information about a plotted star (STAR VIEWER).

  • Utilities Menu
    1. Target Data...: Creates the Target Data widget to give more detailed information about the current plot.
    2. Module/Pointing data...: Creates the Pointing Information widget to give more detailed information about each module and each footprint.
    3. FOV on Map: Creates a tool that displays a cylindrical map projection of the target body.
    4. FOV on Rings: Creates a tool that displays a projection of the ring plane.
    5. Star Viewer...: Creates the Star Viewer widget to display information about selected plotted stars.
    6. Star Limits...:Creates the Star Limits widget to control which magnitude and/or spectral type stars are plotted.
    7. Deep Space Network: Creates the Deep Space Network tool widget. This is a user-developed tool that is not maintained with CASPER.
    8. Preferences...: Creates the Colour Setup widget for changing the colour scheme for the plot.
    9. Display Text File.. Allows the user to view any text file they choose.

  • Shortcut Buttons

    • The shortcut buttons are used to access often used functions more quickly than by going to the Target menus.

    From left to right the buttons are:

    1. New Plot...: Creates the Session Data Entry widget to allow you to enter the parameters for a new plot to be created. If there is an existing plot, you will be given a chance to save or discard the data from that session.
    2. Print Plot: Sends the current plot to the currently selected printer. The printer selection may be changed via the Printer Setup widget available via the file menu on the CASPER widget.
    3. Modules...: This creates the Modules Selection Window for selection of a module create.
    4. Delete Last Module: This deletes the most recently created module.
    5. Load Module: This allows the user to load a previously saved mosaic selected via a Pickfile widget. If there is already pointing data on the plot, the user is prompted to save it. Loading the mosaic will also load the target that the mosaic was originally plotted with. This is an advantage over C-Kernels.
    6. Save Module: This allows the user to save the current observation to a file selected via a Pickfile widget.
    7. FOV Select: This creates the Field of View Selection Window where the user you may toggle FOVs on and off.
    8. Load C Kernel: This allows the user to load a previously saved C Kernel by opening the C Kernel Viewer tool.

      9.  
    9. Plot Mode Next to the shortcut buttons is a display that shows the current plot mode. This mode changes depending on whether you are creating Mosaics or plotting a C Kernel. All functions are available in Mosaic mode, but creation of mosaics and associated functions are unavailable in C Kernel mode. In other words, C Kernels and Mosaics don't mix.

     
  • Main Plot Area

    • The large main graphics area is where the plots are displayed, There are three scroll bars and associated buttons that are linked to the plot area.

    The horizontal scroll bar and left vertical scroll bar are used to move the plot. After each manipulation, the plot is recalculated (you are NOT sliding a plot larger than the display area).The Arrow buttons may be clicked on to give small increments in position.

    The right vertical slider controls the Zoom of the plot.

    The Reset button at the junction of the position sliders will center the plot again, and reset the zoom to the starting value.

    The size of the plot area can be set within the casper_personal_setup shell script to be from around 400 x 400 to 750 x 750 pixels in size.

    Clicking in the main plot window with MB3 will create the Illumination Angles widget showing illumination details and other data about the selected point. 

  • Message Area

    • At the bottom of the window is a text widget that is used to display informational messages to the user. These may be indications of the current processing within CASPER, error messages, etc. A record of these messages can be displayed with the command history option from the menu Main Help.
     
  • Target Data

    • Target Name :                Name of target specified in the session data entry widget.
    Target ID :                     CASPER ID code of this target.
    Target Angular Rate:    The spin rate of the target as seen from the observer.
    Radius 1,2,3 :                Three radii of target body.
    Plot Time (UTC) :        The current time of the plot.
    Target RA/Dec :            Position of target body in space.
    Distance to Target Center (km) :    Distance from spacecraft to center of target body.
    Distance to Target Surface (km) :    Distance from spacecraft to surface of target body.
    Sub Solar Point Lat/Lon :                Position on target body directly below the sun projection.
    Sub Observer Point Lat/Lon :        Position on target body directly below the spacecraft.
     
  • Module/Pointing Data

    • Pointing Index :                Specifies the footprint for which data is being displayed.
    Module Number :             Specifies which module the pointing index corresponds with.
    UTC :                                The actual time for the selected pointing index in UTC format.
    ET :                                    The ephemeris time.
    S/C Clock :                        The ET of the spacecraft clock.
    Duration of Module :        The total time it takes to complete this module.
    Right Ascension :              RA coordinate for the pointing index.
    Declination :                      Dec. coordinate for the pointing index.
    Latitude :                            Target's latitude at the boresight of the selected pointing index.
    Longitude :                         Target's longitude at the boresight of the selected pointing index.
    Twist :                                The twist angle of the instrument.
    Phase Angle :                     The angle between the sun and the spacecraft.
    Solar Angle :                     The angle the sun makes with the target's pole.
    Emission Angle :               The angle between the vector from the target to the observer, and the target's pole.
    Constraint Violation Data :    Information about constraint violations encountered for the particular footprint.
                The following constraints are checked:                 Note:  The ORS radiators and the SRUs are along the same axis and are referred to interchangeably here.


    This tool displays a cylindrical projection of the target body, in latitude and longitude coordinates.  Fields of view are displayed on this map if a module is currently defined within Target.  The sub-spacecraft point is indicated by the S/C symbol, and the sub-solar point is indicated by the SSP symbol.  The limb and terminator are also shown.  In the example above, the limb is shown in blue, and the terminator in brown.  This tool is used for the BODPSCAN module to draw a path on the target body.  The display in this tool may be saved for later printing.  In the pointing menu options, Reset removes all old mosaics from the display, Append allows the user to load and display a previously saved mosaic, and Save saves the currently displayed mosaics to a file.


    This tool is a projection of the Saturn equatorial plane.  The coordinates are in units of Saturn radii (defined to be 60330 km).  Saturn itself is not displayed in this tool.  Two different coordinate systems for longitude are possible: Body East longitude, which is the standard NAIF Saturn body longitude system, and Ring longitude, which is measured from the ascending node of the ring plane on the J2000 X-Y plane (Earth's equator at J2000).  The display may be set to three different zoom levels.  This tool will display the projection of any module on the ring plane, and is used to define a path for the RINGPSCAN observation.  The plots shown in this tool may be saved to a file for printing.