AstroGrav (Windows) 1.7.1

• Basic concepts of mass, position, velocity, acceleration, force, momentum, and energy.
• Kepler's Laws of Planetary Motion and Newton's Law of Gravitation.
• Many body systems and the n-body problem.
• Orbits and Lagrange points.
• Interchange of potential energy and kinetic energy in gravitational systems.
• Projectiles and escape velocities.
• Gravitational slingshots used in space missions.

• Astronomers interested in studying the evolution of gravitational systems.
• Teachers and educationalists seeking to deliver courses on math, physics, or astronomy.
• Students of math, physics, or astronomy.
• Anyone else interested in studying how objects move and interact under the force of gravity.
  

Major Features:

1. Display the distance, speed, magnitude, and phase of selected objects.
2. Display the angles between objects.
3. Change the magnification and brightness of the window.
4. Show or hide the names of objects.
5. Show or hide the velocities of objects.
6. Show or hide the accelerations of objects.
7. Show or hide the orbits of objects.
8. Show or hide the coordinate axes.

Enhancements:

1. Speeds of Selected Objects
   Version 1.7.1 of AstroGrav includes the addition of an object's speed to its label on a model window. If you select an object on a model window, you will now see its name, distance, speed, and magnitude (plus phase for a non-luminous object) displayed next to it in a condensed form. Like the other quantities, the speed is relative to the current viewpoint, so that it will change when you move your viewpoint even if the system is not evolving at the time.
   
2. Expanded Information Popups
   Version 1.7.1 of AstroGrav includes an improvement to the information popups that appear when you hover the mouse over an object on a model window. The speed and magnitude (plus phase for a non-luminous object) have been added to the name and distance that were displayed previously. This means that an information popup now displays the same information that is displayed next to a selected object, so that you can now see this information without having to select the object.
   
3. Other Improvements
   
   • A bug has been fixed that could prevent the program from running at all on a small proportion of Windows PCs.
   • A preview panel has been added to the color chooser, and this shows both the old and the new color so that you can easily compare the two.
   • A bug has been fixed that could cause unwanted gaps to appear in velocity, acceleration, and coordinate axis lines on model windows.
   • A bug has been fixed that could cause the program to crash after attempting to edit a non-editable field in the object editor.
   • The standard keyboard shortcuts for closing windows have been added to the About, Model Navigation, and Choose Color dialogs.
   • There are several minor performance improvements.
   • There are several corrections and minor improvements to the documentation and tutorial. 

Requirements: 500 MHz PowerPC G3 processor, Mac OS X 10.2 minimum, 128 MB RAM, 50 MB disk space