The Solar System Inspector (Asteroids, Comets, and Planets)

When a new comet is found, especially one that will have a close-earth approach, it is handy to have a utility to display its trajectory relative to the other planets.  The Solar System Inspector is Rendezvous' way to do this.  It will display the orbits of selected bodies as thick ropes which makes it much easier to distinguish which orbits lie in front of others.  Let's run through an example and display the trajectory of Comet.  Perform the following steps:

1)  Set the date to January 1, 1997.

2)  Set the time to Midnight GMT, 0:00:00

3)  Load the Target browser from the file Rendezvous.app/States/Comets.hce
(If you don't know how to do this, see the discussion for loading targets)

4)  Load the Target browser from the file Rendezvous.app/States/PolynomialPlanets.list
(If you don't know how to do this, see the discussion for loading targets)

5)  Select the Comets entry in the Targets browser by clicking on it.

6)  Select comet Hale-Bopp in the column which was just displayed by double-clicking on it.

7)  Select the PolynomialPlanets entry in the Target browser by clicking on it.

8)  Select these targets by double-clicking on each of them:

Mercury
Venus
Earth
Mars
Jupiter
Saturn

7)  Bring up the Solar System Inspector by clicking on the "Inspectors : Solar System" button
in the main menu

Rendezvous displays the Solar System Inspector panel which should look like this:

There are several things to be said about this panel.  First, the viewpoint of the display uses the Sun as its origin, and the camera is looking straight down into the plane of the solar system.  The red line pointing to the right is the direction of the Vernal Equinox and is nominally the X axis in helio-centric coordinates.  The red line pointing toward the top is the Y axis, and of course, our eye is located on the positive Z axis looking in the negative Z direction.  We can see the planets Mercury, Venus, Earth, and Mars in increasing distance from the Sun.  Comet Hale-Bopp is coming in above the solar system from the lower right.  It's difficult to see its orbit from this orientation, because our camera just happens to be in its orbital plane.  We can re-orient ourselves by click-dragging the mouse within the view.  As we drag the mouse, the latitude and longitude in helio-centric coordinates will be displayed.  If we orient the view to latitude 6.0 degrees and longitude 270 degrees, we will see a view which looks like this:

From this angle it is much easier to see how the comet comes in from below the plane of the solar system, pops up above it, and then dives back down below.

The controls on the right side of the panel allow you to display the state vector (position and velocity, or orbital element set) for any object in the display.  In the panel above we are displaying the orbital element set for Hale-Bopp in helio-centric ecliptic coordinates.  The value e is the eccentricity (very nearly 1, a parabola, in this case).  The value i is the inclination (very nearly 90 degrees, or perpendicular to the plane of the solar system, in this case).  Omega is the longitude of the ascending node, omega is the argument of perigee, and nu is the true anomaly.