StarryOrbits Help

Please visit the StarryOrbits support forum if you need more help.

Installation
StarryOrbits is installed using Sun's Java WebStart technology. This downloads and installs all the necessary files to your computer and then runs StarryOrbits for you. After you run StarryOrbits for the first time, WebStart will run it from the files stored on your computer. WebStart will automatically download any application files that have been updated since the last use.

You need to have Java version 1.6 (also called Java 6) installed on your computer for StarryOrbits to work. Note that Apple has yet to release Java 1.6 on its Intel chipped 32 bit Macs.

You should first download some of the example animation files from the Animations page.

Then, click here to install and run StarryOrbits. This link will also run StarryOrbits after you have installed it without any further downloads.

''StarryOrbits was programmed in NetNeans and has a 6 month security certificate automatically generated by NetBeans. This means that you will receive a Java security message when you try to run it. You can safely ignore this message.''

''StarryOrbits was programmed and tested on Microsoft Windows XP and Vista. It should also run under Java on other operating systems. Please record any bugs you find under the StarryOrbits development page.''

Operation
Use the File.Open menu to start a new simulation or open the simulation that you want to watch. Once the simulation is running you can rotate and pan your view by clicking and dragging the left and right mouse buttons. Zooming in and out is achieved by turning your mouse wheel.

Use the animation controls in the top toolbar to control the simulation playback and use the View menu commands to toggle display of the various parts of the 3D scene. It is not possible to show any tracks when a simulation is being generated.

Animation Controls
The animation controls are on the top toolbar as follows:

Spheres- and Spheres+
These decrease or increase the size of the spheres which represent the bodies in the simulation. Bodies with more mass have larger spheres.

Track- and Track+
These only work when View.Show Individual Track is selected. They show the entire 3D track of the previous or next body.

Speed- and Speed+
Slow down or speed up the animation.

Pause/Play
Pause or resume playback of the animation. During playback, the current time is shown in the status bar and the playback slider reflects this as well. When paused, you can drag the playback slider to any time you want.

Buttons
When paused, use these buttons to step backwards or forwards by one time step.

New Spherical Collapse Simulation
Generates new simulation based on a spherical cloud of randomly spaced, non-moving bodies. You should enter the follwing information:

- Number of bodies (N)

- Time to stop simulation

- Time between data being saved to output file

- Radius of spherical cloud

- Minimum and maximum mass factors. Masses are initially assigned randomly to each body between a minimum and maximum value. A minimum factor of 0.2 means that no body will have a lower value than 0.2/N. A maximum value of 50.0 means that no body will be heavier that 50/N. All masses are then adjusted so that the total mass of the system is 1.0.

- Name and location of output file

StarryOrbits will then step through the simulation until it reaches the stop time. Press the Stop Simulation button if you want to stop sooner. StarryOrbits then loads and displays the simulation output file. If the new file does not load automatically then use File.Open Existing Simulation.

The simulation code was converted from the original c++ code from "Moving Stars Around. A Preliminary Version of what will expand into Volumes 1,2,3 of the series The Art of Computational Science by Piet Hut & Jun Makino".

Snapshots are automatically generated at the start and end of each simulation.

New Simulation from Snapshot
Generates new simulation from an existing snapshot file. You should enter the follwing information:

- Name and location of snapshots file

- Additional time to run simulation

- Time between data being saved to output file

- Name and location of output file

StarryOrbits will then step through the simulation until it reaches the stop time. Press the Stop Simulation button if

you want to stop sooner. StarryOrbits then loads and displays the simulation output file. If the new file does not load automatically then use File.Open Existing Simulation.

The simulation code was converted from the original c++ code from "Moving Stars Around. A Preliminary Version of what will expand into Volumes 1,2,3 of the series The Art of Computational Science by Piet Hut & Jun Makino".

New snapshots are automatically generated at the start and end of each simulation.

Open Existing Simulation
Displays a file dialog in which you can select the simulation file you want to watch. The file loading progress is shown in a progress bar in the bottom status bar.

Convert Grav-Sim Orbit File
Constructs a StarryOrbits animation file from a Grav-Sim orbit file and displays the animation. You can also reduce the StarryOrbits file size by specifying the time between frames in the dialog that is displayed. This also allows you to give all your animations the same time between frames.



StarryOrbits will then save your new file, reload it and display it.

You may want to run StarryOrbits with more memory as shown here if you are converting large files.

Details on how to generate Grav-Sim orbit files are here.

Exit
Exits StarryOrbits.

Show Toolbar
Hides or shows the top toolbar.

Show Status Bar
Hides or shows the bottom status bar which displays status and help messages.

Change Background Color
Changes the background color - the default is black.

Show Spheres
Hides or shows the spheres that show the positions of each body.

Show Tails
Hides or shows a comet like tail for each body. Note that the tails slow down larger simulations and are turned off by default for simulations with more than 200 bodies.

Show Individual Track
Hides or shows the complete 3D track of a single body. Use the Track- and Track+ buttons to change the displayed track.

Show All Tracks
My personal favourite. Displays the complete 3D tracks of all the bodies in the simulation. Use the View.Hide and View.Section menus to show cutaways and slices of the view.

Show Axes
Hides or shows the xyz origin and axes.

Show Grids
Hides or shows square grids on the XZ and/or XY and/or YZ planes. Each grid runs from -10 to +10 with grid lines at intervals of 1.

Hide Options
Hides selected halves of the 3D scene to show the internal structure of simulations. This is especially usefull when View.Show All Tracks is selected. Hiding 2 halves will show a quarter of the scene and hiding 3 halves will only leave an eighth.

Sections
Shows a cross section of the simulation in the specified plane. This is especially usefull when View.Show All Tracks is selected. Combine sections and hide options as you wish.

Help Menu
Note that some browsers do not allow themselves to be launched from StarryOrbits.

Web Help
Launches your web browser and takes you to this page.

StarryOrbits Home
Launches your web browser and takes you to the StarryOrbits home page.

GravSim Home
Launches your web browser and takes you to the GravSim home page.

MODEST Home
Launches your web browser and takes you to the MODEST Wiki home page.

Credits Screen
Displays the 3D credits animation.

Personal Splash Screen
Displays a 3D credits animation with your choice of message and number of spheres.

Memory Usage
Displays the status of the memory used by StarryOrbits. See Viewing Large Files below if your simulation requires more memory.

File Format
The file format for StarryOrbits simulation data files is shown here.

Viewing Large Files
StarryOrbits is assigned memory by the version of Java on your computer. This defaults to a very low value such as 64MB which is enough to show the current example simulations.

Click on these links to launch StarryOrbits with more memory to view larger simulation files.

StarryOrbits with 200MB - StarryOrbits with 400MB - StarryOrbits with 800MB - StarryOrbits with 1600MB- StarryOrbits with 128TB.