Cassini Image Browser Quick User Guide

Image Browser is a browser for Cassini orbit image. This user guide will describe the pointing violation constraint check, and
coordinate systems. A screen capture of the orbit image browser is shown below.

the browser has three panels. They are shown and described below.

Orbit Selection panel

This panel is used to select the Cassini orbit. The control panel has a pull down menu containing choice of orbit number. The Cassini orbit can be changed to next or previous orbit by pressing the arrow buttons on the right or left. The right button is for the next orbit, and the left button is for the previous orbit.

Image type Control Panel

The control panel is used to choose different image type. The control panel has a pull down menu containing choice of image types, Currently, seven different images are provided:

    - Cassini trajectory in SZS coordinate system. (Saturn Equatorial System).
           Z-axis = Saturn Spin Axis
           Y-Axis = Z-Axis cross (Saturn to Sun Line)
           X-Axis = Y x Z
    - Lemms Coverage - (spacecraft -Z axis looking at the Earth)
    - Lemms Coverage - (spacecraft -Z axis looking at the Sun)
    - Lemms Coverage - (spacecraft -Yaxis looking at the Saturn)
    - Chem Coverage - (spacecraft -Z axis looking at the Earth)
    - Chem Coverage - (spacecraft -Z axis looking at the Sun)
    - Chem Coverage - (spacecraft -Yaxis looking at the Saturn)
    - Chem Coverage - (spacecraft -Yaxis looking at the Saturn - flow outside the bow shock)

Display Panel

This panel is in the panel below the orbit selection panel. It contains two panels, and it displays
images according to the image choice.

    Trajectory in SZS -
                 Top Panel     - Cassini trajectory projection in XY plane
                 Bottom Panel- Cassini trajectory projection in XZ plane

    LEMMS Coverage:
                 Top Panel -   It provides the pitch angle between the spacecraft Y axis and Magnetic field,
                                      the twist angle when the maximum pitch angle occurs, also the distance from
                                      Saturn to Cassini in Saturn radii unit (RS) when the spacecraft poinitng is valid.
                 Bottom Panel - white ares indicates the pointing violation zone
                                      - color map indicates the maximum pitch angle between the spacecraft Y axis
                                          and Magnetic field for the range from 0 to 90 degrees.

   CHEM Coverage:
                 Top Panel -   It provides the minimum angle between spacecraft negative X axis and
                                      plasma flow among all the twist angle rotations when the spcecraft pointing is valid
                                      and plasma velocity projection on the spacecraft is inside the CHEM field of view
                 Bottom Panel - white ares indicates the pointing violation zone
                                      - blue zone indicates the minimum pitch angle for plasma velocity projection is
                                          outside CHEM field of view when the spacecraft pointing is valid
                                      - red zone indicates the minimum pitch angle for plasma velocity projection is
                                          inside CHEM field of view when the spacecraft pointing is valid

Coordinate System Definition:
    SZS:
            Z-axis = Saturn Spin Axis
           Y-Axis = Z-Axis cross (Saturn to Sun Line)
           X-Axis = Y x Z
    spacecraft -Z axis looking at Earth
           Z-axis = pointing from Earth to Cassini
           Y-Axis = Z-Axis cross (Satrunn spin axis)
           X-Axis = Y * Z
    spacecraft -Z axis looking at Sun
           Z-axis = pointing from Sun to Cassini
           Y-Axis = Z-Axis cross (Satrunn spin axis)
           X-Axis = Y * Z
   spacecraft -Y axis looking at Earth
           Y-axis = pointing from Saturn to Cassini
           X-Axis = Y-Axis cross (Saturn spin axis)
           Z-Axis = X * Y