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Version 5.1 - 8th April 2024
The following information is intended for existing users who are already familiar with AstroGrav and want to quickly find out about the main changes.
Version 5.1 of AstroGrav is an upgrade containing a large number of improvements, bug fixes, and performance improvements. If you already have a copy of AstroGrav, all you need to do is to download Version 5.1 and use it in place of your old version. If you have any problems with this new version, please don't hesitate to contact us so that we can help you out.
Version 5.1 of AstroGrav has the following new and improved features.
Importing Asteroids
Version 5.1 of AstroGrav includes the following improvements to importing asteroids with the Edit / Import Objects... command.
- The eight Trojan asteroid categories have been replaced with the corresponding eight Co-orbital asteroid categories.
- The general Trojan asteroid category has been added between the Hilda and Centaur categories. This is identical to the old Jupiter Trojan category.
The easiest way to study a co-orbital asteroid is to import it, use the evolver settings to set the time step to the orbital period of the associated planet, and then run the simulation either forward or backward. The associated planet will then appear stationary in a view window, making it easy to observe the relative motion of the asteroid.
When this is done, co-orbital asteroids fall into one of the following sub-categories, although it is possible for an individual asteroid to occasionally move from one sub-category to another.
- Trojan: The asteroid always stays on one side of the line joining the planet and the Sun.
- Horseshoe: The asteroid crosses the far side of the line joining the planet and the Sun, going part way round, reversing direction, going part way round, reversing direction, and so on.
- Transition: The asteroid goes round and round, occasionally reversing direction.
- Consistent: The asteroid goes round and round, always in the same direction.
If the associated planet is one of the giant planets, it's a good idea to first use the Tools / Calculate Orbits... command to ensure that orbits are being calculated relative to the barycenter of all inferior objects, and to use the Edit / Remove Objects... command to remove the inner solar system. Removing the inner solar system makes the simulation evolve much more quickly, which is important when evolving with time steps as long as the orbital periods of the giant planets.
Importing Earth Satellites
Version 5.1 of AstroGrav enhances the Edit / Import Objects... command with the addition of an option to import Earth satellites. This option works differently from the comet and asteroid imports, because instead of selecting objects from tables, you paste two- or three-line elements into an empty text area. These two- or three-line elements may be obtained from CelesTrak or any other source.
View Window Improvements
Version 5.1 of AstroGrav includes the following improvements to view windows.
- A new View / Turn Around command has been added, which switches the active view window to view in the opposite direction, which is a 180 degree rotation of the viewpoint.
- A new View / Configure Data... command has been added, which allows you to choose which of the following items of object data to display on a view window.
- Distance allows you to show or hide the distances of objects from the viewpoint.
- Velocity allows you to show or hide the velocities of objects relative to the viewpoint.
- Angular Diameter allows you to show or hide the angular diameters of objects as seen from the viewpoint.
- Magnitude allows you to show or hide the magnitudes of objects as seen from the viewpoint.
- Phase allows you to show or hide the phases of non-luminous objects as seen from the viewpoint.
- Phase Angle allows you to show or hide the phase angles of non-luminous objects as seen from the viewpoint.
- In solar system simulations, the View / Configure Tracks... command has been enhanced with the addition of longest and shortest time periods, which determine exactly what is displayed on labels. For example, if you want labels in the form Feb 17, 18:36, you specify a longest time period of Months and a shortest time period of Minutes, and if you want labels in the form 18:36:15.8, you specify a longest time period of Hours and a shortest time period of Deciseconds.
- The Phase Angle of non-luminous objects has been added to the view window popups.
Other Improvements
Version 5.1 of AstroGrav also has many other minor improvements and bug fixes, including the following.
- The Mac version of AstroGrav now runs natively on Apple processors, instead of requiring Rosetta 2.
- On Windows, the list of recently used simulations has been moved from the bottom of the File menu to the new File / Open Recent menu.
- Searching for background stars with the Edit / Find... command has been made more flexible by accepting verbose search strings such as 'Hipparcos 37442' and 'Tycho 1373-1766-1'.
- In the Edit / Add Family... command, the true longitude has been replaced with the much more useful mean longitude.
- A bug has been fixed that prevented the Window / New Ephemeris command from working if the Earth was missing from the simulation.
- The File / Print... command has been modified to allow a greater compression of printouts before splitting them over two or more pages.
- The February Hydrids sample simulation has been updated so that the meteoroids have equally spaced mean longitudes, instead of equally spaced true longitudes.