AstroGrav Changelog

What's new in AstroGrav 5.1

Apr 9, 2024

Replaced the eight Trojan asteroid categories with the corresponding eight Co-orbital asteroid categories in the Edit / Import Objects... command, facilitating the study of Trojan, Horseshoe, Transition, and Consistent co-orbital asteroids.
Enhanced the Edit / Import Objects... command with the addition of an option to import Earth satellites.
Added a new View / Turn Around command, which switches the active view window to view in the opposite direction.
Added a new View / Configure Data... command, which allows you to choose which of items of object data to display on a view window.
In solar system simulations, enhanced the View / Configure Tracks... command with the addition of longest and shortest time periods, which determine exactly what is displayed on labels.
Made searching for background stars with the Edit / Find... command more flexible, by accepting verbose search strings such as 'Hipparcos 37442' and 'Tycho 1373-1766-1'.
Various minor bug fixes and improvements.

New in AstroGrav 5.0.1 (Oct 30, 2023)

New in AstroGrav 5.0 (Oct 9, 2023)

Evolution Improvements:
Version 5.0 of AstroGrav includes a new evolution algorithm, which is much more accurate than any of its predecessors, and which contains several bug fixes and performance improvements. Errors have been greatly reduced when evolving solar system simulations.
Ephemeris Generation:
Version 5.0 of AstroGrav includes the following improvements to the generation of ephemerides.
Ephemeris windows have been enhanced to have multiple tabs, with the first tab showing the current ephemeris data for every object, and the other tabs showing ephemerides for individual objects.
Ephemerides can now be generated for locations on the Sun, Moon, and planets, as well as for locations on the Earth.
The ephemeris generation command has been moved from Tools / Generate Ephemeris... to Window / New Ephemeris.
Location Improvements:
Version 5.0 of AstroGrav includes the following improvements to the handling of surface locations.
The locations editor has been extended to allow locations on the Sun, Moon, and planets, instead of just on the Earth.
The locations of all successful landings on the Moon, Mars, and Venus have been added.
The View / ViewFrom... command has been enhanced to allow viewing from locations on the Sun, Moon, and planets, instead of just from locations on the Earth.
The term altitude has been replaced with the term elevation, to avoid confusion with angular altitude.
Sample Simulations:
Version 5.0 of AstroGrav includes the following improvements to the sample simulations.
The sample simulations have been completely revised and reorganized.
Many new sample simulations have been added, so that there are now a total of 89 of them.
The Solar System / +Basic sample simulations have been updated from 01/07/2022 to 01/01/2024.
Several new Kuiper Belt Objects (KBOs) have been added to the basic solar system sample simulations.
Other Improvements:
Version 5.0 of AstroGrav also has many other minor improvements and bug fixes, including the following.
The Mean Motion has been added to the choice of orbital elements when adding or editing objects, in order to support the use of two-line elements (TLEs).
Date units now show the time zone where appropriate, instead of just displaying local time.
Nutation has been added to the Earth's precession.
Several user operations have been speeded up, particularly the opening of simulations.
Color randomization has been greatly improved in the Edit / Split Object... command, so that it is now much easier to distinguish the individual objects that result from a split.
A bug has been fixed that made it impossible to edit an object, except in a solar system simulation.
A bug has been fixed that caused AstroGrav to crash in some circumstances while drawing tracks.
A bug has been fixed that caused inaccurate data to be displayed in a background star's window when planetary aberration was switched on.
Magnitude calculations have been made more accurate.

New in AstroGrav 4.5.3 (Aug 25, 2022)

New in AstroGrav 4.5.2 (Jul 17, 2022)

New in AstroGrav 4.5.1 (Jun 16, 2022)

New in AstroGrav 4.5 (May 23, 2022)

Importing Objects:
Version 4.5 of AstroGrav includes the following improvements to importing asteroids and comets with the Edit / Import Objects... command.
The asteroid tables have a new Brighter Than... category, which allows you to quickly find asteroids that are brighter than a specified magnitude on a particular date and time.
The asteroid tables have a new Closer Than... category, which allows you to quickly find asteroids that are closer than a specified distance on a particular date and time.
The asteroid tables have a new Faster Than... category, which allows you to quickly find asteroids that are faster than a specified angular velocity on a particular date and time.
The asteroid tables have a new Within... category, which allows you to quickly find asteroids that are close to a specified point on the celestial sphere on a particular date and time.
The accuracy of the magnitudes of imported asteroids has been greatly improved.
The asteroid and comet tables now display hyphens instead of default values in cells with unknown values, to better reflect the original website data.
A bug has been fixed that caused the hundreds digits of Lowell asteroids' inclinations to be omitted.
The Small Body tab has been added to the preferences dialog, allowing you to change the addresses from which the downloaded data is obtained if necessary.
Manually Drawn Angles:
Version 4.5 of AstroGrav includes the following improvements to the manual drawing of angles on view windows by dragging the mouse from one point to another while holding down the Control and Shift keys (Command and Shift keys on a Mac).
A manually drawn angle remains until it is manually removed, which is done by re-drawing the angle.
Manually drawn angles never disappear automatically, as they did in earlier versions of AstroGrav.
Manually drawn angles are saved to disk, so that you can still see them when a simulation is re-opened.
Manually drawn angles are visible on snapshots taken with the Tools / Take Snapshot... command.
Manually drawn angles are visible on a duplicate window that is created with the Window / Duplicate... command.
Background Stars:
Version 4.5 of AstroGrav includes the following improvements to the display of information about background stars in a solar system simulation.
Rise, transit, and set times have been added to the background star popups when viewing from a location on the Earth.
Planetary Aberration, Refraction, and Use JNow checkboxes have been added to the information window that is displayed after double-clicking on a background star.
The time zone has been added to the information window that is displayed after double-clicking on a background star.
Faint background stars can now be double-clicked to display an information window, in the same way as the main background stars.
Table Fonts:
Version 4.5 of AstroGrav includes the following changes to the display of tables.
The font used for tables has been changed to a monospaced font, to ensure that exported table data (as shown in a text editor) exactly matches the table data as displayed in AstroGrav.
A Font chooser has been added to the table preferences, which provides a choice of suitable monospaced fonts for displaying tables.
The default column widths of all types of table have been adjusted to take into account the change to a monospaced font.
The sample simulations have been updated to reflect the change to a monospaced font in tables.
The display of table data has been speeded up to be about twice as fast as it was in earlier versions of AstroGrav.
Printing:
Version 4.5 of AstroGrav includes the following improvements to the printing of simulation windows using the File / Print... command.
A printout now only overflows onto a second page if it's really necessary.
A printout now only takes as few pages as is reasonably possible, with the printout scaled to minimize the amount of white space.
The default page orientation has been changed from portrait to landscape on view windows and table windows. This only affects new windows and new simulations - existing simulations are not automatically updated.
The sample simulations have all been updated so that their view windows and table windows have landscape as their default page orientation.
A bug has been fixed that could leave a view window's colors inverted after cancelling its print dialog.
Other Improvements:
Version 4.5 of AstroGrav also has many other minor improvements and bug fixes, including the following.
Various minor improvements have been made to the sample simulations.
Planetary Aberration, Refraction, and Use JNow checkboxes have been added to the information window that is displayed after double-clicking on an object in a solar system simulation.
When created from a view window, an ephemeris table now copies its initial Planetary Aberration setting from the view window.
A bug has been fixed that could cause centering to be inaccurate after using the Edit / Find... command.
A bug has been fixed that could cause the points on view window tracks to be missing, or to be displayed in the wrong places.
A bug has been fixed that caused the collision time to be inaccurate when searching for a collision with the Evolve / Evolve To... command.
A bug has been fixed that could cause orbits to be displayed in the wrong place when planetary aberration was switched on.

New in AstroGrav 4.4.3 (Dec 7, 2021)

Importing Objects:
Version 4.4.3 of AstroGrav includes the following improvements to importing asteroids and comets with the Edit / Import Objects... command.
The data source (JPL, MPC, or Lowell) and the epoch can now be appended to names independently of each other.
The asteroid and comet tables have been resized so that they just fit horizontally, without the need for any horizontal scrolling.
The algorithm for detecting Trojan asteroids has been improved.
A bug has been fixed that caused orbital elements to fail to be calculated after importing objects with the Fast Import option.
The asteroid and comet tables now auto-resize their columns as specified in the Auto-Resize Columns setting of the table preferences.
An asteroid with an absolute magnitude greater than 50 now has its absolute magnitude set equal to 50, to avoid creating unrealistically small asteroids.
A bug has been fixed that sometimes caused the progress bar to bobble back and forth while evolving to an import epoch.
Ephemeris Generation:
Version 4.4.3 of AstroGrav includes the following updates to generating ephemerides with the Tools / Generate Ephemeris... command.
An ephemeris table now maintains the positions and widths of its columns when a simulation is saved and re-opened.
The default width of the Epoch column of an ephemeris table has been increased to accommodate the longer date formats.
The accuracy of an ephemeris table's refraction calculations has been improved.
A bug has been fixed that left a single row ephemeris table unchanged after changing the viewing location.
A bug has been fixed that left a single row ephemeris table unchanged after changing one of the Planetary Aberration, Refraction, or Use JNow settings.
Other Improvements:
Version 4.4.3 of AstroGrav also has many other minor improvements and bug fixes, including the following.
The Solar System sample simulations have been updated to 01/01/2022, and also have several other minor improvements.
A bug has been fixed that caused the latest solar system sample simulations to open with views from London instead of from the home location.
A table now always displays its vertical scroll bar, row scroller, and help button, regardless of the table's contents.
The calculation of orbital elements has been greatly speeded up in simulations containing a large number of low-mass objects.
A bug has been fixed that could cause the three animated dots on a status bar to continue animating after evolution was completed.
A bug has been fixed that caused date/time formatting to simply drop any excess digits, instead of rounding to the nearest millisecond.
A bug has been fixed that could cause orbits to be drawn in the wrong place when View / Show / PlanetaryAberration was switched on.
Orbital elements are now recalculated when necessary after using the Evolve / Settings... command.

New in AstroGrav 4.4.2 (Oct 13, 2021)

New in AstroGrav 4.4.1 (Sep 7, 2021)

New in AstroGrav 4.4 (Aug 6, 2021)

Evolution Improvements:
Version 4.4 of AstroGrav includes major improvements to the evolution algorithm. This provides many benefits, and in particular, greatly improves the accuracy of solar system simulations in most situations.
Improved Searching:
Version 4.4 of AstroGrav includes the following updates to finding objects and celestial positions with the Edit / Find... command.
An option has been added for finding a particular right ascension and declination on a solar system simulation's view window.
An option has been added for finding a particular azimuth and altitude on a solar system simulation's view window.
After an object has been found on a view window, it is now circled (like a background star) rather than selected, so that there is no longer an automatic change to the objects selected.
Trajectories and Histories:
Version 4.4 of AstroGrav includes the following improvements when drawing the trajectories and histories of objects.
Trajectories and Histories are no longer treated separately, but have been combined into Tracks that have characteristics of either or both.
The View / Show All / Trajectories and View / Show All / Histories commands have been replaced with the single View / Show All / Tracks command.
The View / Show Selected / Trajectories and View / Show Selected / Histories commands have been replaced with the single View / Show Selected / Tracks command.
The View / Trajectories... command has renamed as the View / Configure Tracks... command, with choices of Lines only, Labels only, and Lines and Labels providing the same functionality as was previously provided by the separate trajectories and histories.
The buttons on the view window tool palettes have been modified to accommodate the above changes.
Other Improvements:
Version 4.4 of AstroGrav also has many other minor improvements and bug fixes, including the following.
Handling invisible objects has been simplified, with the View / Show All / Invisibles and View / Show Selected / Invisibles commands being replaced with the single View / Show / Invisible Objects command.
The Hilda asteroid category has been added to the tables that are shown with the Edit / Import Objects... command.
A bug has been fixed that caused the Earth's rotational position to be out by about a minute.
The column selectors at the top-left of tables have been modified so that they no longer close automatically when an item is selected.
The drawing of background stars has been speeded up.
Plus ('+') symbols are now allowed in exponents when editing angles.
The error message that is displayed after entering a negative Family Size in the Edit / Add Family... command has been corrected.

New in AstroGrav 4.3.1 (Feb 1, 2021)

New in AstroGrav 4.3 (Jan 25, 2021)

New in AstroGrav 4.2.2 (Oct 11, 2020)

New in AstroGrav 4.2.1 (Oct 6, 2020)

New in AstroGrav 4.2 (Aug 21, 2020)

New in AstroGrav 4.1.1 (Jan 15, 2020)

New in AstroGrav 4.1 (Dec 23, 2019)

New in AstroGrav 4.0 (Jul 4, 2019)

New in AstroGrav 3.7.1 (Jan 4, 2019)

New in AstroGrav 3.7 (Nov 20, 2018)

Evolution Improvements:
Version 3.7 of AstroGrav includes the following additions to the Evolve / Evolve To... command when using solar system simulations:
Evolution to the next or previous perihelion of any chosen object.
Evolution to the next or previous aphelion of any chosen object.
Evolution to the next or previous ascending node of any chosen object.
Evolution to the next or previous descending node of any chosen object.
Other evolution improvements in Version 3.7 of AstroGrav include the following:
There are significant improvements to both the accuracy and the speed of evolution.
A bug has been fixed that could cause simulations with tight binaries to evolve extremely slowly.
A bug has been fixed that could cause the evolution algorithm to fail when using bouncing collisions in complex situations.
File Import and Export:
Version 3.7 of AstroGrav includes new File / Import... and File / Export... commands that allow you to export a simulation to a tab-separated text file, modify this text file with a text editor or spreadsheet software, and then import the modified text file into a new simulation. This can be useful if you want to change many objects at once, as it can be much faster than using the Edit / Edit Object... command individually on each of the many objects.
Other Improvements:
Version 3.7 of AstroGrav also has many other minor improvements and bug fixes, including the following:
Open... and Save As... buttons have been added to the preferences dialog so that preferences can easily be backed up or copied from one computer to another.
Custom locations have been moved from the bottom to the top of the list of locations.
Inaccuracies converting between rectangular and orbital elements have been greatly reduced.
Several minor improvements have been made to the star dialog that is displayed after double-clicking on a background star in a solar system simulation.
The Edit / Remove Objects... and Edit / Merge Objects... commands have been made more accurate.
The keyboard shortcuts of the View menu and its submenus have been changed so that the meta key is no longer required on Windows.
A bug has been fixed that caused an object window's Edit Object... button to remain enabled after its object had been removed from the simulation.

New in AstroGrav 3.6 (Apr 12, 2018)

Evolving To Events:
The next or previous opposition of any chosen object.
The next or previous conjunction of any chosen object.
The next or previous quadrature of any chosen object.
The next or previous transit of any chosen object.
The next or previous minimum elongation of any chosen object.
The next or previous maximum elongation of any chosen object.
The next or previous minimum distance of any chosen object.
The next or previous maximum distance of any chosen object.
Importing Objects:
The Edit / Import Objects... command reads data from web addresses at the International Astronomical Union's Minor Planet Center that have recently changed. As a result, earlier versions of AstroGrav are now unable to read this data, and the import tables appear empty. Version 3.6 of AstroGrav fixes this problem, and also includes the following improvements to the importing of asteroids and comets.
In the event that no data is found when attempting to refresh an import table, AstroGrav now reverts to the cached table, rather than overwriting the cached table with an empty table.
The Near-Earth descriptive popup has been corrected in the Category boxes of asteroid and comet import tables.
Help Menu Improvements:
A new Help / AstroGrav Facebook command has been added that takes your default browser to the Facebook page that is associated with AstroGrav.
A new Help / Email Support command has been added that creates a new email in your default email client that is addressed to the AstroGrav support service.
Other Improvements:
The Tools / Create Movie... command has been improved to show hundredths of a second in the display of the movie time.
Various simulation settings (such as the last sought object) are now saved along with a simulation so that they appear as defaults the next time the simulation is used.
The umlauted character in Boötes has been corrected so that it now displays correctly.
The notes of the sample simulations have been corrected so that accented characters now display correctly.
Windows are no longer unnecessarily reordered before displaying save or exit/quit confirmation dialogs.
Several performance improvements have been made, significantly speeding up some operations.

New in AstroGrav 3.5.1 (Dec 27, 2017)

New in AstroGrav 3.5 (Dec 9, 2017)

HIGHLIGHTS:
Introduced a new evolution algorithm that is both more accurate and significantly faster in many simulations.
Made several improvements and bug fixes to the import of asteroids and comets with the Edit / Import Objects... command.
Made several improvements to the handling of tables.
Added a new Edit / Remove Objects command that removes the current selection of objects in such a way as to leave the orbits of other objects unchanged.
Made many performance improvements, significantly speeding up some operations.
Removed inaccuracies in the calculation of peri longitude and position longitude values.
Corrected a fault that could cause object histories to appear on the inside of trajectories where they could overlap and be difficult to read.
Various minor bug fixes and improvements.
SIMULATION EVOLUTION:
Version 3.5 of AstroGrav includes a new evolution algorithm that is both more accurate and significantly faster in many simulations.
IMPORTING OBJECTS:
Version 3.5 of AstroGrav includes the following improvement and bug fixes to the importing of objects into solar system simulations using the Edit / Import Objects... command.
A bug has been fixed that caused the import of asteroids to fail in a rare cases, such as the recently discovered interstellar asteroid 2017 U1.
A bug has been fixed that could cause AstroGrav to do a fast import even when the Fast Import box was deselected.
AstroGrav's guess for the absolute magnitudes of comets has been increased from 12 to 15 when the JPL Comets option is used, so that comets don't appear to be much brighter than they actually are. The MPC Comets option, which contains accurate absolute magnitudes, is unchanged.
Importing objects is now much faster in cases where a significant amount of evolution is required.
TABLE IMPROVEMENTS:
Version 3.5 of AstroGrav includes the following improvement to tables.
A bug has been fixed that caused characters such as degree, arcminute, and arcsecond symbols to appear as other symbols when the exported files were opened in text editor or spreadsheet software.
A bug has been fixed that caused the headers of an exported table to be incorrect after a change of units.
The Show Horizontal Scroll Bar item in a table's column selector menu has had its name changed to Auto-Resize Columns, because this better reflects its purpose. The corresponding change has also been made in the table preferences.
The column resizing algorithm has been improved to make it easier to manually resize a table's columns when Auto-Resize Columns is switched on.
Ephemeris tables have been made to respect the Auto-Resize Columns setting in the table preferences.
The Total Velocity column has been added to ephemeris tables. This is hidden by default, but can be shown using the table's column selector.
Many of the column widths in ephemeris tables have been reduced so that less 'junk digits' are displayed and ephemeris windows take up less space.
REMOVING OBJECTS:
In previous versions of AstroGrav, the only way to remove objects from a simulation was to use the Edit / Delete command. This has the disadvantage that the orbits of other objects are changed as a consequence. For example, if you delete the Moon from a solar system simulation, the Earth's orbit is significantly changed as a consequence. Version 3.5 of AstroGrav solves this problem with the introduction of a new Edit / Remove Objects command that removes the current selection of objects in such a way as to leave the orbits of other objects unchanged.
OTHER IMPROVEMENTS:
Version 3.5 of AstroGrav also has many other minor improvements and bug fixes, including the following.
Many performance improvements have been made, significantly speeding up some operations.
Inaccuracies in the calculation of peri longitude and position longitude values have been removed.
A bug has been fixed that could cause object histories to appear on the inside of trajectories where they could overlap and be difficult to read.
The entry of exponents has been made more flexible by allowing upper case 'E' characters and '+' symbols.
Unwanted '-' symbols for dimensionless units have been removed from various parts of the user interface.
The Calculate Orbits... command has been moved from the Edit menu to the Tools menu.
The Solar System sample simulations have been made more accurate, and their start date has been changed from 01/01/2017 to 01/01/2018.

New in AstroGrav 3.4.3 (Sep 1, 2017)

New in AstroGrav 3.4.2 (Aug 4, 2017)

New in AstroGrav 3.4.1 (May 17, 2017)

Importing Objects:
The Edit / Import Objects... command reads data from addresses at NASA's JPL site that have recently changed. As a result, earlier versions of AstroGrav are now unable to read this data, and the import tables appear empty. Version 3.4.1 of AstroGrav fixes this problem, and also includes the following improvements to the importing of asteroids and comets.
The sorting of the huge asteroid tables shown with the Edit / Import Objects... command has been speeded up.
Descriptive popups have been added to the Category boxes of asteroid and comet import tables.
The default export filename of an asteroid or comet import table has been improved.
View Windows:
Version 3.4.1 of AstroGrav includes the following improvements to the way that view windows operate.
Celestial grids are now displayed correctly at very high magnifications.
Background star searching in solar system simulations with the Edit / Find... command has been enhanced to allow searching on any of the following catalogue numbers or designations.
Harvard Revised No
Flamsteed Designation
Bayer Designation
Durchmusterung ID
Henry Draper No
Hipparcos No
Tycho No
Background star searching in solar system simulations with the Edit / Find... command has been greatly speeded up, although this will probably only be noticeable on slower computers.
The frequent unwanted 180° flips of azimuth labels has been removed.
The tendendancy for longitude labels to jump from one side of a longitude line to the other has been greatly reduced.
Constellation skeleton lines running to or from the viewpoint are now suppressed when viewing from a background star that forms part of a constellation's skeleton.
Object Windows:
Version 3.4.1 of AstroGrav includes the following improvements to the way that object windows operate.
Long object names have been truncated so that object windows are no longer too wide as a consequence.
The popups on labels have been improved so that they include the appropriate object's name.
Descriptive popups have been added to the celestial coordinates boxes.
The popups on celestial coordinates labels have been improved so that they contain more useful information.
The popups on celestial coordinates values have been improved so that they are displayed to the maximum possible accuracy.
New Units:
Version 3.4.1 of AstroGrav includes the following new units.
The lunar distances unit has been added to the distance units.
The modified julian days unit has been added to the date units. This is evaluated as JD-2400000.5, where JD is the number of Julian days.
Other Improvements:
Version 3.4.1 of AstroGrav also has many other minor improvements and bug fixes, including the following.
An object's editor can now be opened immediately by double-clicking on the object with the Alt key depressed. This provides an alternative to selecting the object and then using the Edit / Edit Object... command.
There are significant improvements to evolution performance.
A bug has been fixed that caused the Edit / Split Object... command to always create a three-dimensional rubble pile regardles of whether a two- or three-dimensional rubble pile was specified.
The Ephemeris preferences have been removed, with the Home Location... button being transferred to the General preferences.
The default export filename of an ephemeris table has been improved.
Many other minor performance improvements have been made.

New in AstroGrav 3.4 (Dec 17, 2016)

New Features:
The choice of object types has been greatly expanded from 8 to about 50, with the inclusion of many subtypes. When an object type is chosen, a dialog message pops up giving you the opportunity to automatically set the color, luminosity, mass, and radius to values that are typical for your selected object type. This speeds up the creation of your own simulations since you no longer need to choose these values explicitly, although you can still override the default settings if you want to.
New View / Show All / Angles... and View / Show Selected / Angles... commands have been added that allow you to display the angles between pairs of objects in a view window.
The new View / Show / Light-Time Correction command has been added that allows you to take into account the finite speed of light in a view window. In many cases, the effect of using this is so small that it might not be visible.
The new View / Show / Grid Guide command has been added that allows you to superimpose a faint grid over a view window. This can be useful if you want to know exactly where the center of a view window is, or if you want to align things horizontally or vertically.
The number of View / Show commands on the tool palette has been increased from four to eight, so that all these commands are now available on the tool palette.
A new Window / Export... command has been added that allows you to export a text representation of the active window's contents. This is ideal for use in a text editor, word processor, or spreadsheet application.
Ephemeris Generation:
The columns of ephemeris tables have been reorganized to make the ordering more logical.
The ephemeris table header popups have been improved to refer to the target object by name instead of generically.
Azimuth and altitude motion have been added to the columns of ephemeris tables.
Emphemeris tables have been simplified by combining the right ascension / declination coordinate motion and sky motion into a single right ascension / declination proper motion.
The rows of ephemeris tables have been made selectable for highlighting purposes.
Object Windows:
Object windows have been redesigned to match the visual style of the new background star windows.
In solar system simulations, ecliptic, equatorial, and horizontal coordinates have been added to object windows that are opened by double-clicking on an object in a view window. As with the other information displayed, these celestial coordinates update continuously as a simulation evolves.
Double-clicking on an object has been modified to open an object window instead of an object editor. If you want to edit an object, you can either use the Edit Object... button on the object window, or use the Edit / Edit Object... command.
The Window/New Object... command has been removed because it no longer serves a useful purpose, and its presence was a source of confusion.
Background Stars:
A background star's information window has been changed from a dialog that must be closed before continuing into a window that can be left open as long as desired. This means that the information shown now changes as necessary as the time and viewpoint changes and that multiple windows for different background stars can be displayed if desired.
Boxes showing ecliptic coordinates, J2000 equatorial coordinates, galactic coordinates, and horizontal coordinates have been added to a background star's information window. These celestial coordinates update continuously as a simulation evolves.
The viewpoint has been added to a background star's information window.
The Flamsteed and Bayer designations have been improved in a background star's information window.
The Tycho designation has been added to a background star's information window.
The View / Fix... command has been enhanced to allow the fixing of background stars in solar system simulations.
The View / View From... command has been enhanced to allow viewing from background stars in solar system simulations.
A bug has been fixed that could cause the Edit / Find... command to fail to find an existing background star in a solar system simulation.
Sample Simulations:
The radii and masses of the asteroids in the Solar System and Planets, Moon, Asteroids simulations have been updated to take into account recent measurements that are much more accurate than before.
Many new Kuiper Belt Objects (KBOs) have been added to the Solar System and Planets, Moon, KBOs simulations.
The start date of the Solar System simulations has been changed from 01/01/2016 to 01/01/2017.
In addition, all of the sample simulations have been modified to make use of the greatly expanded range of object types.
Other Improvements:
The simulation of rubble piles has been significantly speeded up.
The mouse wheel sensitivity on view windows has been adjusted so that it is now consistent for all magnifications and fields of view.
A Use this as my home location choice has been added to the location editor that is displayed with the Tools / Edit Locations... command. This allows you to select the location that you want to use as the default for creating an ephemeris with the Tools / Generate Ephemeris... command. A home location selector has also been added to the Ephemeris tab of the preferences.
The Position unit has been renamed the Distance unit.
The Default Selection labels have been renamed Restore Defaults labels.
The keyboard shortcut of the Edit / Reverse Objects command has been changed from Alt+Control+R (Alt+Command+R on a Mac) to Alt+Control+V (Alt+Command+V on a Mac) to resolve the conflict with the keyboard shortcut of the Evolve / Step Backward command.
A bug has been fixed that could cause AstroGrav to crash if a view window's fixed object was deleted.
A bug has been fixed that could cause AstroGrav to crash if a view window had the horizon fixed and the Earth was deleted.
A bug has been fixed that caused the headers and units to appear in the same cell of an exported table.

New in AstroGrav 3.3.3 (Jul 29, 2016)

Feature Improvements:
The Edit / Import Objects... command has been enhanced with the addition of a Year... option to the choice of categories on the asteroid and comet tables. This allows you to filter a table of thousands of asteroids or comets to show just the ones that were discovered in a particular year.
The View / Show All / MOIDs... and View / Show Selected / MOIDs... commands previously only displayed the minimum orbit intersection distances (MOIDs) between pairs of elliptical orbits that had a shared focus. These commands have now been greatly improved to include parabolic, hyperbolic, and anti-hyperbolic orbits, as well as orbits that don't share a common focus.
The setting up of exoplanet systems has been made easier with the addition of the jupiter masses and jupiter radii units.
The accuracy of ephemeris table calculations with Light-Time Correction has been improved in the Tools / Generate Ephemeris... command.
Evolution with general relativity is now slightly more accurate and slightly faster.
The Evolve / Settings... command has had a Sound Effects setting added that allows you to play sound effects whenever two objects collide and combine.
The Edit / Import Objects... command has been modified to return to the Import Objects dialog when an asteroid or comet table is canceled.
Sample Simulations:
The sample simulations have been modified to make much better use of larger screens.
The Solar System sample simulations have been updated to use the ICRF/J2000.0 reference frame. Earlier versions of these simulations included a small translation of the reference frame that has now been removed, so that objects' position and velocity components now exactly match those provided by the NASA/JPL HORIZONS system.
The Planets, Major Moons sample simulation has had the number of major moons increased to include all 21 moons with masses greater than 3.019kg.
The mass of Neptune's moon 2004N1 has been changed from 6.018kg to 6.015kg in the Solar System and Planets, All Moons sample simulations.
The name of the planet KOI 377.03 has been changed to Kepler 9 d in the Kepler 9 sample simulation.
The Tutorial.ast simulation has been transferred from the sample simulations to a separate download that is made from within the tutorial itself.
Other Improvements:
A bug has been fixed that prevented AstroGrav from starting up correctly in locales for which there is no set of sample simulations.
A bug has been fixed that caused the mass threshold and radiation pressure settings to be ignored when displaying a re-opened simulation.
A bug has been fixed that caused the incorrect display of the anti-hyperbolic orbits that arise when repulsive radiation pressure exceeds gravitational attraction.
Editing the mass of an object has been modified so that it no longer leaves the parent family's barycenter unchanged, but instead leaves the positions and velocities of all objects unchanged.
The Edit / Add Object... and Edit / Add Family... commands have been modified to allow zero mass objects.
A bug has been fixed that could cause a disk error to be reported when trying to save changes to a read-only simulation. A more appropriate message is now displayed.
When the startup option is to open the latest simulation and the recent file list is empty, the file chooser is now displayed instead.
The system error messages that were written when a user lacked administrator privileges have been removed.

New in AstroGrav 3.3.2 (Apr 25, 2016)

A wide range of minor improvements and bug fixes, including the following:
The Edit / Date/Time... command has been improved for non-solar system simulations by allowing you to switch between dates and times if desired, and also by providing you with a choice of units instead of restricting you to the simulation's unit.
The Evolve / Evolve To... command has been improved by providing you with a choice of units instead of restricting you to the simulation's unit.
The Edit / Import Objects... command has been modified to ensure that the 'Fast Import' checkbox is always initially deslected, in order to avoid the possibilty of accidental inaccurate imports of asteroids and comets. The progress dialog has also been improved so that it progresses at a much more uniform rate.
The order of the files in the File / Open Recent... menu has been changed from the order in which the files were last opened to the order in which the files were last closed. As a consequence, when AstroGrav is configured to open the latest simulation on startup, the most recently closed simulation is the one that is automatically opened when AstroGrav starts up.
A bug has been fixed that could cause the View / Show All / Distances... and View / Show Selected / Distances... commands to calculate incorrect values.
A bug has been fixed that could cause the View / Show All / MOIDs... and View / Show Selected / MOIDs... commands to fail in some circumstances.
The Edit / Edit Object..., Edit / Add Object..., and Edit / Add Family... commands have been modified to allow luminosities to be editable with all types of particles.
The drawing of trajectories with the View / Show All / Trajectories... and View / Show Selected / Trajectories... commands has been improved to avoid drawing unwanted cusps at sharp turns in the trajectories.
A bug has been fixed that could cause the Evolve / Evolve To... command to evolve to the wrong time when using the fractional days unit.
The default set of units that is used when creating a new simulation has been changed from SI units to units that are more suitable for an astronomical simulation.
The default mass threshold of a new simulation has been changed from zero to 1020 kilograms, and the default time step of a new simulation has been changed from 1,000 seconds to 0.01 days.
The default radii, luminosities, and masses of the objects in the Edit / Add Family... command have been changed to more useful values.
A bug has been fixed in the Tools / Create Movie... command that caused an obscuring window to appear in a movie when the 'Entire Window' option was being used.
The order of the constellations in the Edit / Find... command has been changed to alphabetic.
The application icon has been replaced with a much improved and more contemporary icon.
The calculation of radiation pressure for zero mass objects has been improved.
Minor improvements have been made to the STEREO and Three Body System sample simulations.

New in AstroGrav 3.3.1 (Apr 2, 2016)

Table Improvements:
All tables that appear in AstroGrav now have a unified look and feel with a column selector button in the top-left corner, a row scroller button in the top-right corner, an export button in the bottom-left corner, and a help button in the bottom-right corner. The export and help buttons are new, with the export button showing a right-pointing arrow, and the help button showing a question mark. The export button on a table window allows the state of the system to be exported to a tab-separated text file - something that was not possible in earlier versions of AstroGrav. The help button displays the table-related documentation.
The export button that appeared below some tables has been removed, since its function is now taken up by the new export button in the bottom-left corner of the table.
The number of lines in table headers has been increased from two to three, so that the displayed text doesn't have to be abbreviated as much as before.
The phase of the target object has been added to the default set of table columns that are displayed with the Tools / Generate Ephemeris... command.
Keyboard Shortcuts:
Ten commands in the Edit menu have had keyboard shortcuts added.
Nine commands in the View menu (and submenus) have had keyboard shortcuts added.
Five commands in the Tools menu have had keyboard shortcuts added.
The Window / Notes command has had a keyboard shortcut added.
A few existing keyboard shortcuts have had to be changed in order to maintain a reasonable consistency in the shortcuts used.
Other Improvements:
The absolute magnitude of the JPL Comets has been increased from 10.0 to 12.0 in the Edit / Import Objects... command. [The absolute magnitude is not supplied with the list of JPL Comets, so AstroGrav has to make a guess.]
More accurate values of the color, radius, and mass of the New Horizons spacecraft have been used in the New Horizons sample simulation. Making these values as accurate as possible is important when radiation pressure is to be taken into account while evolving the simulation.
The size of newly opened windows has been increased.
The gap at the left of status bars has been removed to make better use of the available space.
On Windows, there are a range of minor user interface changes and performance improvements.
On a Mac, the missing RGB color chooser has been added for use when choosing the color of an object.

New in AstroGrav 3.3 (Mar 4, 2016)

NEW FEATURES:
New View / Show All / Distances... and View / Show Selected / Distances... commands have been added that allow you to display the distances between pairs of objects.
New View / Show All / MOIDs... and View / Show Selected / MOIDs... commands have been added that allow you to display the minimum orbit intersection distances (MOIDs) between pairs of orbits.
A new Help / AstroGrav Google+ command has been added that takes you straight to AstroGrav's Google+ site in your default browser. This allows you to view and reply to all the latest posts related to AstroGrav.
A new Date Format button has been added to the general preferences that allows you to choose between 15 different date formats, instead of being restricted to just a single date format as in earlier versions of AstroGrav. The default date format remains the same.
Importing Objects:
A table of asteroids or comets can now be filtered to show only objects in the Potentially Hazardous category. This is defined in the usual way as objects with an absolute magnitude below 22, and whose minimum orbit intersection distance (MOID) is less than 0.05 astronomical units. At the time of writing this produces tables of 1,681 potentially hazardous asteroids and 199 potentially hazardous comets, many of which are fragments of comet 73P/Schwassmann-Wachmann 3.
Several new comet categories have been added, increasing the number of categories from five to twelve. This now allows you to filter a table of comets to show only objects in one of the following categories: Kreutz Sungrazers, Meyer Sungrazers, Kracht Sungrazers, Marsden Sungrazers, General Sungrazers, Potentially Hazardous Comets, Jupiter-Family Comets
The 'Ctrl+A' ('Cmd+A' on a Mac) keystroke for selecting all rows now works on a table of asteroids or comets without having to first select something in the table.
Earth Locations:
40 major astronomical observatories have been added to the standard list of Earth locations.
A bug has been fixed that could cause accented characters to display incorrectly in the names of Earth locations.
If you open a simulation (typically provided by somebody else) that uses an Earth location that is not known to your copy of AstroGrav, this location will automatically be added to your list of locations so that you can use it yourself.
Other Improvements:
The Mac OS X installation process has been improved to make it as simple as possible.
The Tools / Create Movie... command has been enhanced to allow a choice of area that is to be visible in the movie. This choice is the same as that provided by the Tools / Take Snapshot... command, and contains the following four options: Main Area Only, Main Area & Status Bar, Entire Window, Entire Screen.
The Tools / Create Movie... command has been improved to ensure that animation is switched on when creating a movie using the Evolve / Evolve To... command. In earlier versions it was very easy to accidentally create a movie with animation switched off, resulting in a useless one-frame movie, and this modification now prevents this from happening.
Improvements have been made to the way that the undo and redo commands work on units and notes windows.
A bug has been fixed that caused a 'Disk I/O error' to be reported when trying to overwrite a read-only simulation file.
The values used for converting to Earth masses or Sun masses have been adjusted slightly so that they exactly match the values used in the sample simulations.
A help button has been added to the preferences dialog that immediately takes you to the relevant page of the AstroGrav documentation.
Some of the German translations have been improved.

New in AstroGrav 3.2.1 (Dec 23, 2015)

New in AstroGrav 3.2 (Nov 26, 2015)

Simulation Evolution:
Version 3.2 of AstroGrav includes the following improvements to the way that simulation evolution works.
The accuracy of solar system evolution has been greatly improved when dealing with close encounters between objects. This includes the evolution of moons and satellites, which are effectively in a permanent state of close encounter with their parent planet.
The Evolve / Evolve To... command has been improved with the addition of an Animate on-off switch. With animation switched on, the command works the same as before, with the simulation's windows being updated after each time step. With animation switched off, the simulation's windows are only updated when evolution is complete, making evolution very much faster in most cases. If non-animated evolution takes more than a couple of seconds, a progress bar is displayed to indicate how long it's going to take and to give you the opportunity to cancel evolution if desired.
The Evolve / Settings... command has been enhanced with the addition of a Radiation Pressure on-off switch. This allows you to include the effect of radiation pressure when evolving a simulation. In most situations, the effect of radiation pressure is insignificant, but it can be an important factor in the evolution of small objects, and the smaller the object, the more significant the effect is. The best known example is the particles in a comet's tail that move in trajectories that are very different from their parent comet as a result of radiation pressure. Spacecraft, being much larger, are affected much less, but radiation pressure is still an important factor in planning their trajectories.
You can easily experiment with the effect of radiation pressure by opening one of the Solar System simulations and greatly increasing the Sun's luminosity. Increasing it by a factor of 1012 produces a small change in the orbits of the planets, a factor of 1013 produces a major change in the orbits of the planets, and a factor of 1014 puts the planets into 'anti'-hyperbolic orbits where the repulsive force of radiation pressure is greater than the attractive force of gravity, causing the planets to accelerate away from the Sun forever. An 'anti'-hyperbolic orbit is indicated by a negative semi-major axis in tables and lists of orbital elements.
Importing Objects:
Version 3.2 of AstroGrav includes the following improvement and bug fixes to the importing of objects into solar system simulations using the Edit / Import Objects... command.
Importing without the Fast Import option is no longer animated, making it much faster than in earlier versions. If importing takes more than a couple of seconds, a progress bar is displayed to indicate how long it's going to take and to give you the opportunity to cancel the operation if desired.
Importing without the Fast Import option now leaves the simulation at the same date and time as it started, instead of leaving it at the date and time of the last object imported.
Importing without the Fast Import option is now even more accurate than in earlier versions as a consequence of the improved accuracy of evolution.
Importing with the Fast Import option is unchanged.
Sample Simulations:
Version 3.2 of AstroGrav includes the following updates to the solar system sample simulations.
When opening one of the Solar System simulations, you now get a dialog displaying the question: Evolve to the present time? If you accept this dialog, the simulation quickly evolves to the current date and time without displaying the state of the system at any of the intermediate times. In many cases this takes less than a second, and if it takes more than a couple of seconds, a progress bar is displayed to indicate how long it's going to take and to give you the opportunity to cancel evolution if desired. If you reject the dialog, the simulation is left at the date and time at which it was last saved. This new feature has exactly the same effect as manually selecting the Evolve / Evolve To... command, leaving the default date and time unchanged, and selecting non-animated evolution.
The Solar System simulations have had the physical elements of Pluto and its moons updated to take into account the recent discoveries made by the New Horizons mission.
The Space Missions simulations have been made more accurate, and have been modified to take into account the effect of radiation pressure.
The start date of the Solar System simulations has been changed from 01/01/2015 to 01/01/2016.
Other Improvements:
Version 3.2 of AstroGrav also has many other minor improvements and bug fixes, including the following.
A bug has been fixed that caused the Help / Report Fault... command to fail to work on some computers.
The list of open windows at the end of the Window menu is now only displayed when there is more than one open window.
The Dutch translations have been greatly improved.

New in AstroGrav 3.1.1 (Sep 29, 2015)

New in AstroGrav 3.1 (Sep 16, 2015)

Has the following new features in the new Tools menu, as well as several improvements to existing features:
Changing Reference Frames
Taking Snapshots
Creating Movies
Generating Ephemerides
Other Improvements
Changing Reference Frames:
Version 3.1 of AstroGrav includes a new Tools / Reference Frame... command that allows you to transform the reference frame so that the barycenter is stationary, at the origin, or both.
Taking Snapshots
Version 3.1 of AstroGrav includes a new Tools / Take Snapshot... command that allows you to take a snapshot of the current display. The following four options are available.
A snapshot of the main area of the active window, excluding both the tool bar and the status bar.
A snapshot of the main area and status bar of the active window, excluding the tool bar.
A snapshot of the entire active window, including the tool bar, the status bar, and the window decorations.
A snapshot of the entire screen, including anything that is visible from other applications or the operating system.
Creating Movies:
Version 3.1 of AstroGrav includes a new Tools / Create Movie... command that allows you to create a movie of a simulation while it is evolving. The following four settings are available.
The Movie Format setting specifies whether to create the movie in AVI format or QuickTime format.
The Frames Per Second setting specifies the number of frames per second and time steps that the movie is to have.
The Compression setting specifies the compromise between small file size and high image quality.
The Include Logo setting specifies whether or not to include an AstroGrav logo in the bottom-right corner of the movie.
Generating Ephemerides:
Version 3.1 of AstroGrav includes a new Tools / Generate Ephemeris... command that allows you to generates an ephemeris for any object in a solar system simulation while it is evolving. You can choose any viewpoint on the Earth, any target object, and any combination of 19 available columns of data in the generated ephemeris table. The time interval between rows of the generated ephemeris table can be set by adjusting the time step with the Evolve / Settings... command. A Light-Time Correction option allows you to choose between an ephemeris of the selected object as it actually is, or an ephemeris of the selected object as it appears to be, taking into account the time that it takes for light to travel from the selected object to the viewpoint.
Other Improvements:
Version 3.1 of AstroGrav also has many other minor improvements and bug fixes, including the following.
The Mac version of AstroGrav no longers requires a Java installation.
The New Horizons sample simulation has been modified to make it much more accurate.
Improvements have been made to the functioning of the Edit / Undo... and Edit / Redo... commands on Units and Notes windows.
Several cosmetic improvements have been made to the View / Customize Tool Bar... dialog, including the addition of a Help button.
The Windows version of AstroGrav has had icons added to the top-level menus (when menu icons are switched on).
The documentation and tutorial have been updated to take into account the recent changes to the software.

New in AstroGrav 3.0.6 (Jun 25, 2015)

New in AstroGrav 3.0.5 (May 8, 2015)

New in AstroGrav 3.0.4 (Mar 20, 2015)

Help Improvements:
The more complex commands have had help buttons added to their dialog windows. These help buttons take the form of square buttons containing a question mark, and when you click on one of them, you are immediately taken to the most relevant page of the documentation. This saves you the trouble of navigating through the documentation to find the appropriate information.
The AstroGrav version number has been added to every page of the documentation, so that you can easily check that you're looking at the documentation that corresponds to your version of AstroGrav.
The documentation for the Edit / Find... command has been rewritten, to bring it up to date.
Viewing Improvements:
Version 3.0.4 of AstroGrav includes the new View / Selections... command. This allows you to choose whether selections are independent in different windows or whether selections are the same in different windows. Previous versions of AstroGrav have always had independent selections in different windows, and this behaviour remains the default with AstroGrav 3.0.4. With this new command, you can opt to have the same selections in different windows, so that when you change the selection in one window, the selection in other windows changes to correspond.
Other Improvements
Version 3.0.4 of AstroGrav also has many other minor improvements and bug fixes, including the following:
The time zone or time unit has been added to the dates and times shown on status bars.
The Edit / Import Objects... command has been improved so that the small body type and Fast import without evolution setting are automatically saved and restored. In most cases, this will reduce the number of times that these have to be set explicitely.
In the Edit / Import Objects... command, the Fast import without evolution checkbox has been moved to the following dialog window, where it is more useful.
A memory leak has been fixed that could cause AstroGrav to run short of memory when large numbers of windows were opened and closed in a simulation.
Various improvements have been made to the documentation and tutorial.

New in AstroGrav 3.0.3 (Feb 13, 2015)

Editing Improvements:
The Edit / Edit Object..., Edit / Add Object..., and Edit / Add Family... commands have been improved to leave the position and velocity of the parent family's barycenter unchanged. In earlier versions of AstroGrav, it was the position and velocity of the parent object itself that was left unchanged, and this improvement results in much smaller changes to the parent's orbital elements after editing. In cases where there is no change of mass, the changes to the parent's orbital elements are now entirely eliminated.
The Edit / Calculate Orbits... command has been added to give you a choice of two different ways of calculating orbital elements. One option is calculate orbital elements relative to the parent object only, and the other option is calculate orbital elements relative to the barycenter of all inferior objects. The difference between these two options is fully explained in the documentation.
A bug has been fixed that caused AstroGrav to crash when an eccentricity of exactly one was entered into the object editor. The handling of near-parabolic cases has also been improved.
Editing an object's eccentricity now leaves the object's true anomaly invariant, rather than its mean anomaly.
Other Improvements:
The value used for the astronomical unit has been changed from 149597870691.0 meters to 149597870700.0 meters - a difference of 9 meters. Since AstroGrav always uses meters internally, this will not affect the way that simulations evolve. The only effect is that distances that are displayed in astronomical units or parsecs will be slightly different.
A bug has been fixed that could prevent a simulation from evolving when collisions were not being ignored.
A bug has been fixed that could cause a simulation to evolve differently depending on the collisions setting, even when no collisions actually occurred.
A color randomizer has been added to the Edit / Split Object... command so that the individual objects in a rubble pile can be easily distinguished.
The extension '.txt' has been added to the default filename of the File / Export... command.
The File / Import.html... command has been enhanced so that it automatically strips out Excel's surrounding double quotes when attempting to parse numbers.
A bug has been fixed that could cause the tool tips of the Edit / Undo and Edit / Redo commands to be incorrect.
Various improvements have been made to the documentation and tutorial.

New in AstroGrav 3.0.2 (Dec 19, 2014)

Added the Edit / Split Object... command to allow the easy conversion of an asteroid, comet, or other object into a rubble pile.
Greatly improved the performance when evolving simulations that contain rubble piles.
Changed the start date of the Solar System sample simulations to 01/01/2015.
Changed the names of comets in the Solar System sample simulations to the standard form that is used in the comet import (Edit / Import Objects...) command.
Added comet C/2014 Q2 (Lovejoy) to the Solar System sample simulations.
Improved the choice of mnemonics used for the items in the Edit menu.
Various minor bug fixes and improvements.
Rubble Piles:
Version 3.0.2 of AstroGrav includes a new command for creating rubble piles, together with a major performance improvement when evolving simulations that contain rubble piles.
The Edit / Split Object... has been added to allow you to easily convert an asteroid, comet, or any other object into a rubble pile. This new command allows you to specify the following.
The number of identical components that the rubble pile is to have.
Whether the rubble pile is to be two-dimensional (a rubble disc) or three-dimensional.
Whether the components are to be numbered or lettered. If the components are numbered, then '-1', '-2', '-3', etc are appended to the names of the components to distiguish them. If the components are lettered, then '-A', '-B', '-C', ... '-Z', '-AA', '-AB', '-AC', etc are appended to the names of the components to distiguish them. Numbering is likely to be the more useful, with lettering provided mainly because this is the standard convention for designating comet fragments.
The rotation period, with a value of infinity used to specify a non-rotating rubble pile.
The x-, y-, and z-components of the rotation axis. Only the direction of this vector is used, so that multiplying all three components by the same positive number will have no effect. Multiplying all three components by -1 will reverse the direction of rotation.
Sample Simulations:
Version 3.0.2 of AstroGrav includes the following updates to the sample simulations.
The start date of the Solar System simulations has been changed from 01/01/2014 to 01/01/2015.
The names of comets in the Solar System simulations have been changed to the standard form that is used in the comet import (Edit / Import Objects...) command. 1P/Halley and C/1995 O1 (Hale-Bopp) are typical examples of the new names.
Comet C/2014 Q2 (Lovejoy) has been added to the Solar System simulations.
The Planets, Asteroids simulation has had the Moon added to it, and has been renamed Planets, Moon, Asteroids to reflect the change.
The Planets, Comets simulation has had the Moon added to it, and has been renamed Planets, Moon, Comets to reflect the change.
The Planets, KBOs simulation has had the Moon added to it, and has been renamed Planets, Moon, KBOs to reflect the change.
Other Improvements:
Version 3.0.2 of AstroGrav also has many other minor improvements and bug fixes, including the following.
The choice of mnemonics used for the items in the Edit menu has been improved. This applies only to the Windows operating system, as Mac OS X doesn't use mnemonics.
The startup process has been changed so that a fresh installation of AstroGrav automatically opens the Planets, Moon sample simulation, instead of opening a newly created simulation.

New in AstroGrav 3.0.1 (Oct 29, 2014)

New in AstroGrav 3.0 (Oct 1, 2014)

VIEW WINDOW IMPROVEMENTS:
In solar system simulations, it is now possible to view from points on the Earth's surface, instead of only being able to view from its center. When you use Alt+Control+Click (Alt+Command+Click on a Mac) on the Earth, you now get a location chooser displayed that allows you to choose a location on the Earth's surface. A list of locations is supplied with AstroGrav, and this contains well over 100 of the world's best known cities, as well as the center of the Earth so that you can still view from the Earth's center if you wish. This list of locations can be edited with the new Edit / Locations... command, so that you can easily add your own location, together with any other locations that are of interest to you.
When you use Alt+Shift+Click on an object that is already fixed, the fixed point changes to the barycenter of the object's family. Repeatedly using Alt+Shift+Click on an object switches between fixing the object itself and fixing the barycenter of the object's family.
The View/Background/Horizontal Grid menu item and tool have been added. This shows the local horizontal (altitude-azimuth) coordinate grid at the point on the Earth's surface that you are viewing from. This command is only available when you are viewing from somewhere on the Earth's surface in solar system simulations.
The View/Background/Horizon menu item and tool have been added. This shows the local horizon at the point on the Earth's surface that you are viewing from, and includes north, south, east, and west indicators. This command is only available when you are viewing from somewhere on the Earth's surface in solar system simulations.
The View/Background/Galactic Grid menu item and tool have been added. This shows the galactic coordinate grid in solar system simulations.
The View/Background/Galactic Plane menu item and tool have been added. This shows the galactic plane in solar system simulations.
When viewing from a location on the Earth's surface, the azimuth and altitude have been added to the top of the star dialog that is displayed after double-clicking on one of the background stars.
By viewing from your location on the Earth's surface with the horizon fixed and displayed, you can use AstroGrav in a similar way to common planetarium software applications. Several of the Solar System sample simulations include a window that has been set up to illustrate this.
When you select the View / View From... command or use Alt+Control+Click (Alt+Command+Click on a Mac) on empty space, you now get a dialog displayed that gives you the following viewpoint options:
Floating leaves your viewpoint floating free in space, and this is the option you got automatically in earlier versions of AstroGrav.
Object allows you to choose an object as your viewpoint, and gives you an alternative to finding the object and using Alt+Control+Click on it (Alt+Command+Click on a Mac).
Location allows you to choose a location on the Earth's surface as your viewpoint, and gives you an alternative to finding the Earth and using Alt+Control+Click on it (Alt+Command+Click on a Mac).
When you select the View / Fix... command or use Alt+Shift+Click on empty space, you now get a dialog displayed that gives you the following options for choosing your fixed point:
Background allows you to fix the background.
Barycenter allows you to fix the barycenter of the system, and this is the option you got automatically in earlier versions of AstroGrav.
Family allows you to fix the barycenter of a chosen family.
Object allows you to fix a chosen object, and gives you an alternative to finding the object and using Alt+Shift+Click on it.
Horizon allows you to fix the horizon when you are viewing from a location on the Earth's surface.
SIMULATION EVOLUTION:
Version 3.0 of AstroGrav includes major improvements to the way that bouncing collisions are handled during evolution. The most significant improvement is that simulations involving large numbers of bouncing collisions (such as rubble piles) have been greatly speeded up. Also, in previous versions of AstroGrav, a friction factor was automatically included in bouncing collisions in order to ensure that a bouncing ball would come to a halt, and not continue to roll forever. In many situations, this friction factor is not wanted. For example, in a simulation of a rotating rubble pile, the rotation rate would decrease and the rubble pile would eventually stop rotating, whereas it ought to continue rotating forever. To solve this problem, an Include Friction checkbox has been added to the dialog that is displayed with the Evolve / Settings... command, and this allows you switch friction on and off as desired. Friction is now switched off by default, and it is recommended that you leave it switched off unless you have a simulation (such as bouncing balls) in which you're sure that it's wanted.
OTHER IMPROVEMENTS:
A bug has been fixed that caused the Evolve / Evolve To... and Edit / Date/Time... commands to fail for users in the western hemisphere (the Americas) when specifying a date.
Many minor improvements have been made to the sample simulations.
The navigation guide that is displayed with the Help / Navigation Guide command has been updated to take into account the recent changes to the software.
The documentation and tutorial have been updated to take into account the recent changes to the software.
The Edit / Date/Time... command has been disabled in solar system simulations because it serves no useful purpose there and occasionally gets confused with the Evolve / Evolve To... command.
The Edit / Import Objects... command has been disabled in any simulation that is running.

New in AstroGrav 2.2.3 (Jun 11, 2014)

View Window Improvements:
The View / Show All / Data command has been added to display the distances, speeds, magnitudes, and phases of the objects when desired.
The View / Show All / Nodes command has been added to display the ascending nodes and descending nodes of the objects when desired.
The View / Show All / Apsides command has been added to display the pericenters and apocenters of the objects when desired.
All three of the new commands in the View / Show All menu have had corresponding tool buttons added to the tool palette. The tool buttons for the little used View / Show All / Objects, View / Show All / Velocities, and View / Show All / Accelerations commands have been removed to make way for the three new tool buttons. These commands are still available in the menu if they are needed.
The View / Show Selected menu has been modified in exactly the same way, with the addition of three new commands and their corresponding tool buttons.
The View / Fix and View / View From commands have been added to provide alternative ways of fixing an object and viewing from an object. These two commands are primarily intended to make AstroGrav easier for beginners to use, and are unlikely to be of interest to experienced users.
Object Import Improvements:
Version 2.2.3 of AstroGrav includes a significant improvement to the Edit / Import Objects... command. There is now a small button in the top-right corner of tables that makes it much easier to scroll to a particular part of a very large table. This button has an Row scroller icon icon and is positioned to the right of the column headers, immediately above the vertical scroll bar. When you click on this button, a small dialog is displayed in which you can type what you are looking for in the column that the table is currently sorted on. If you OK this dialog, AstroGrav will immediately scroll to the part of the table containing whatever you typed. While this is mainly intended for use in very large tables, it is also available in any other table that has a vertical scroll bar.
Other Improvements:
A bug has been fixed that caused the buttons in a tool palette to be left aligned instead of evenly spaced.
The terms peri and ap have been changed to pericenter and apocenter, both in the user interface and the documentation.
Several of the tool icons have been improved.
The documentation and tutorial have been updated to cover the recent improvements.

New in AstroGrav 2.2.2 (May 12, 2014)

View Window Improvements:
The View / Show / Trajectories.html and View / Show / Histories.html commands have been greatly improved so that they now work correctly with all combinations of viewpoints and fixed objects.
The View / Show / Histories.html command has been changed so that the dates and times that are marked exactly match the dates and times of evolution.
The ecliptic grids and equatorial grids have been made easier to read by showing more latitude and longitude labels.
The dialog that is displayed after double-clicking on a background star has had the date and time added to it.
Editing Improvements:
The old Edit / Add Object... and Edit / Add Child... commands have been combined into a single Edit / Add Object... command that first shows a small dialog that lets you to choose the parent of the new object.
The dialog that is displayed after selecting the Edit / Add Family... command has had a Parent field added to it, so that you no longer have to select the parent before choosing the command.
The Edit / Import Objects... command has been improved so that comets are imported with their names in the standard form of 1P/Halley, C/1995 O1 (Hale-Bopp), etc.
The Edit / Find... command has been enhanced to include a pop-up menu that shows objects whoses names match whatever has already been typed.
Evolution Improvements:
Evolution has been greatly speeded up when using the General Relativity option.
A bug has been fixed that sometimes caused collisions to be handled incorrectly.
Performance on multi-processor and multi-core computers has been improved.
Improvements have been made that now allow simulations of the Sun and planets to be evolved over periods of tens of millions of years without significant error (although things like this take a long time to run).
The Evolve / Evolve To... command now saves the latest setting of the Beep when finished flag, so that you shouldn't need to change it as often as before.
Several other minor improvements and bug fixes have been made to the evolution algorithm.
Other Improvements:
There are now separate default folders for simulation ('.ast') files, export ('.txt') files, and new family pattern ('.xml') files, so that there should now be less need to navigate between folders when choosing files.
Menu tips have been added that pop up when the mouse hovers over a menu item, together with an option to switch these off in the preferences if they're not wanted.
The solar system sample simulations have been improved so that comets now have their names in the standard form of 1P/Halley, C/1995 O1 (Hale-Bopp), etc.
Several of the tool icons have been improved.
The skeleton of the constellation Camelopardalis has had two lines added to make it look (vaguely) like a giraffe.
The documentation and tutorial have been updated to cover the recent improvements.

New in AstroGrav 2.2.1 (Feb 19, 2014)

New in AstroGrav 2.2 (Nov 27, 2013)

Includes a new evolution algorithm that contains the following improvements.
The Newton: Fast and Newton: Accurate choices have been replaced with a single Newtonian choice, so that it no longer necessary for you to choose between speed and accuracy.
Both speed and accuracy are much improved in most simulations.
Energy conservation has been greatly improved in stable systems (such as the solar system and exoplanet systems), so that it is now possible to run such simulations over very long periods of time.
In earlier versions of AstroGrav, any object whose mass was less than the mass threshold was treated as if it had zero mass, resulting in a pair of objects being treated incorrectly if one object's mass was above the mass threshold and the other object's mass was below the mass threshold (eg, the Earth-Moon pair with a mass threshold of 1.0e23 kg). This problem has been solved by changing the meaning of the mass threshold so that the interaction between pairs of objects is ignored if and only if their mass sum is less than the mass threshold.
Includes the following updates to the sample simulations:
The evolution algorithm used in the sample simulations has been updated to the new AstroGrav 2.2 evolution algorithm.
The mass threshold used in the solar system sample simulations has been reduced from 1.0e22 kg to 1.0e21 kg, because Pluto's system of moons is poorly simulated with a mass threshold greater than the mass of Charon.
Three recently discovered moons of Jupiter (2011J1, 2011J2, and 2000J11) have been added to the Solar System simulations.
The recently discovered fourteenth moon of Neptune (2004N1) has been added to the Solar System simulations.
The recently discovered fifth moon of Pluto (Styx) has been added to the Solar System simulations.
Comet ISON (C/2012 S1) and Comet Siding Spring (C/2013 A1) have been added to the Solar System simulations.
Several new Kuiper Belt Objects have been added to the Solar System simulations.
The radius and mass of Pluto and Charon have been updated in the Solar System simulations.
The start date of the Solar System simulations has been changed from 01/01/2012 to 01/01/2014.
The Voyager simulation has been updated so that it is no longer necessary to manipulate the view window to watch the entire simulation.
Other Improvements:
Version 2.2 of AstroGrav also has many other minor improvements and bug fixes, including the following.
On view windows, the display of any coordinate axis that is pointing almost straight in or straight out of a window is now suppressed, so that two-dimensional simulations no longer show the unwanted third coordinate axis.
Several minor improvements have been made to the star dialog that is displayed after double-clicking on one of the background stars in a solar system simulation.
The keyboard entry of dates (with times) in the Edit / Date/Time... and Evolve / Evolve To... commands has been made more flexible and less insistent on a particular format.
The formatting of values to a number of significant digits has been improved by no longer removing trailing zeros.
The status bar has been improved so that the labels no longer jump back and forth when running a simulation.
A bug has been fixed that caused orbits with inclinations of exactly 180 degrees to get drawn incorrectly.
A bug has been fixed that sometimes caused orbital elements to be calculated incorrectly when a non-zero mass threshold was in use.

New in AstroGrav 2.1.2 (Aug 29, 2013)

New in AstroGrav 2.1.1 (Jul 26, 2013)

New in AstroGrav 2.1 (Jul 1, 2013)

Evolution of very large systems has been greatly speeded up, particularly ones in which most objects have masses below the evolution mass threshold.
A bug has been fixed that made evolution inaccurate when general relativity was being used. In most cases, the inaccuracy was very small, but could be large for near-parabolic orbits.
Bouncing collisions have been greatly improved, so that it is now possible to simulate rubble piles and their collisions. A bug has also been fixed that caused simulations with bouncing collisions to produce different results on different runs with multi-processor/core computers.
A bug has been fixed that occasionally caused the Evolve / Evolve To... command to fail to complete, particularly when using a long time step.
A bug has been fixed that could cause a two-dimensional system (such as one in which the z-coordinate of every object is zero) to evolve into a three-dimensional system.
A bug has been fixed that could cause some updates of view windows to be omitted when running a simulation, resulting in jerky animation.
A bug has been fixed that could cause processing power to continue to be used after evolution had been stopped.
Major performance improvements have been made for handling simulations that contain a large number of objects.
Closing windows and exiting/quitting AstroGrav have both been greatly speeded up.
A bug has been fixed that could cause negative angles to get rounded incorrectly.
A bug has been fixed that often caused the right ascension '0h 00m' to be overlaid with '24h 00m' on the display of the celestial equator.
A bug has been fixed that caused the fixed object on a view window to fail to revert to the center of mass following its deletion.
A bug has been fixed that caused the fixed object on a view window to fail to remain fixed after deleting the object being viewed from.
The name of the View / Background / Less Star Names command has been changed to View / Background / Fewer Star Names.
Support has been added for Retina displays.

New in AstroGrav 2.0.2 (Dec 27, 2012)

View Window Improvements:
Includes the following improvements and bug fixes to the operation of view windows.
There have been several improvements made to the display of ecliptic grids and equatorial grids. The details of these improvements can be found below.
In solar system simulations, ascending node indicators and descending node indicators have been added to the orbits of selected objects that have the Sun as a parent.
The magnitude key has been made much more useful by making the magnitudes of the key stars sensitive to the magnification and brightness.
The crosses indicating selected objects have been made visible regardless of whether or not the object itself is bright enough to be visible.
A bug has been fixed that caused AstroGrav to crash when viewing from the single object in a simulation with just one object.
Trajectory drawing and history drawing have been significantly speeded up.
A bug has been fixed that caused some history values to disappear near the edge of a window.
Coordinate Grid Improvements:
Includes the following improvements and bug fixes to the display of ecliptic and equatorial coordinate grids on view windows.
The display of ecliptic grids and equatorial grids has been greatly speeded up at high magnifications.
More ecliptic grid lines and equatorial grid lines are now displayed at low magnifications.
A bug has been fixed that caused some angle labels on the ecliptic and the equator to not be displayed when they should be.
A bug has been fixed that caused angle labels on the ecliptic and the equator to jump from one side of the line to the other at low magnifications.
The orientation of the angle labels used for the ecliptic and the equator have been changed from parallel to horizontal.
Object Import Improvements:
Includes the following improvements and bug fixes to the Edit / Import Objects... command.
A bug has been fixed that caused the fragment codes of comets to be missing from comet import tables.
In asteroid import tables, the Name column has been renamed the Designation column.
In asteroid import tables, the default sort column has been changed from the Number column to the Designation (previously Name) column.
In asteroid import tables, sorting on the Designation column has been greatly improved to make it more intuitive and easier to manually search for a particular asteroid.
Other Improvements:
Has many other minor improvements and bug fixes, including the following.
A bug has been fixed that could cause an edited orbital period to become corrupted when using the object editor.
The Tau Ceti sample simulation has been added in order to illustrate the system of five planets that have recently been found to be orbiting the star Tau Ceti.
In most of the sample simulations in the Abstract Systems and Exoplanet Systems, the origin of the reference frame has been made stationary at the center of mass.
The documentation has been updated to cover the recent improvements.

New in AstroGrav 2.0.1 (Nov 12, 2012)

Evolution Improvements:
The evolution algorithm has been multi-threaded, so that it runs significantly faster on multi-processor and multi-core computers.
A bug has been fixed that caused the General Relativity option to be very unreliable in some circumstances.
Animated evolution has been significantly speeded up on multi-processor and multi-core computers by using one processor/core to update the screen display while a second processor/core works on calculating the following state of the simulation.
The handling of collisions with the Combine option has been improved to correct a fault that could cause evolution to grind to a halt when a collision occurred.
The handling of collisions with the Bounce option has been improved to correct a fault with the evolution of simulations in which multiple bounces occur close together.
The results of multiple single steps are now identical to the results of a single run over the same time period - something that wasn't the case in earlier versions of AstroGrav.
Background Star Names:
The Solar System, Solar System 2, and Space Missions sample simulations have been adjusted so that choosing the View / Background / Star Names command immediately shows a reasonable number of star names. In AstroGrav 2.0, it was sometimes necessary to choose the View / Background / More Star Names command many times before any star names actually appeared.
The name of the View / Background / Fewer Star Names command has been changed to View / Background / Less Star Names.
The View / Background / Less Star Names command is now disabled whenever all star names are hidden.
The View / Background / More Star Names command is now disabled whenever all star names are shown.
Sample Simulations:
The accuracy of the data has been improved in the Comet Gehrels 3 sample simulation.
The Comet Oterma sample simulation has been added.
The Solar System, Solar System 2, and Space Missions sample simulations have been adjusted so that choosing the View / Background / Star Names command immediately shows a reasonable number of star names. In AstroGrav 2.0, it was sometimes necessary to choose the View / Background / More Star Names command many times before any star names actually appeared.
The Collapsing Cloud sample simulation has been modified to make the stars different colors, so that they can easily be distinguished when they've collected together after running with bouncing collisions.
In non-English installations of AstroGrav, the default sample simulation folder has been changed from the English sample simulation folder to the the appropriate non-English sample simulation folder.
Other Improvements:
A bug has been fixed that could cause AstroGrav to crash on Windows PCs with Intel Core i7 processors.
A bug has been fixed that could cause a crash when trying to find the object that the viewpoint is attached to in a view window.
A bug has been fixed that caused closing and re-opening a tool palette to result in an empty tool palette, without any tools.
The positioning of a new tool palette has been improved so that it no longer obscures part of the window that it belongs to.
When you choose the File / Save command or the File / Save All command, an 'Are you sure?' message is now displayed before overwriting an existing simulation file, so that it is harder to accidentally overwrite a file that you want to retain.
The font size used for the constellation names that are displayed with the View / Background / Constellation Names command has been significantly reduced.
The default coordinate axis color in view windows has been changed from white to orange.
The tutorial has been updated to cover some of the more recent features.

New in AstroGrav 2.0 (Aug 7, 2012)

New in AstroGrav 1.9.4 (Dec 10, 2011)

New in AstroGrav 1.9.3 (Oct 24, 2011)

New in AstroGrav 1.9.2 (Jul 4, 2011)

New in AstroGrav 1.9.1 (Mar 31, 2011)

New in AstroGrav 1.9 (Mar 19, 2011)

Evolving:
Version 1.9 of AstroGrav includes several corrections to minor faults in the evolution algorithm that could affect evolution accuracy. These faults are all of a subtle nature, and were most likely to be noticed when studying comets in solar system simulations, when occasionally a comet would slowly wander away from its correct path.
There is also a significant performance improvement in the evolution algorithm. This varies from one simulation to another, but is typically around 15 percent faster.
Sample Simulations:
Much more accurate masses (several significant figures) have been used for the major bodies of the solar system, which has the effect of reducing errors in solar system simulations by well over 99 percent.
27 recently discovered large Kuiper Belt Objects (KBOs) have been added.
The start date has been changed from 01/01/2010 to 01/01/2011.
The Tutorial sample simulation has been updated to have a start date on 01/01/2011, and the text of the tutorial has been updated to correspond.
In addition, the Spiral Arms sample simulation has been updated so that the disturbing galaxy approaches on an eccentric orbit rather than having a circular orbit.
Units:
Units have been made easier to read on tables by changing from one-line table headers to two-line table headers.
On the Edit/Units... dialog, the order of the units in the popup lists has been improved.
The arcminutes and arcseconds units have been replaced with the degrees : minutes and degrees : minutes : seconds units respectively.
The grads : centigrads and grads : centigrads : centi-centigrads units have been added.
The date and date + time units have been renamed the fractional days and local time units respectively.
The universal time unit has been added.
The symbols used for Earth radii, Solar radii, Earth masses, Solar masses, and Solar luminosities have been changed to use the single Sun and Earth characters.
Other Improvements:
A bug has been fixed that could cause table sorting to only partially sort the objects.
A bug has been fixed that could cause a slight modification of a simulation's state whenever a view window was opened.
The Edit / Date/Time... and Evolve / Evolve To... dialogs have been improved to allow minutes and seconds to be omitted without reporting an error.
A bug has been fixed in the File / Import... command that caused the time unit to be ignored when importing a simulation.
A bug has been fixed in the File / Export... command that caused the time in an exported file to always be expressed in seconds, regardless of the specified unit.
A bug has been fixed that could cause the animated series of dots on a status bar to appear when they shouldn't.
The display of data in tables has been speeded up.

New in AstroGrav 1.8.4 (Oct 30, 2010)

Made many improvements to the sample simulations.
Added a "beep when finished" checkbox to the Evolve / Evolve To... dialog.
Corrected a fault that could cause a highly eccentric orbit (such as Comet McNaught's) to be inaccurately displayed.
Corrected a fault that could cause unwanted orbit lines to be displayed with a highly eccentric orbit (such as Comet McNaught's).
Improved the algorithm used to calculate the magnitude of a non-luminous body.
Simplified the installation of AstroGrav on Windows Vista and Windows 7.
Made table column selectors focusable, so that column selection can be done with the keyboard.
On view windows, made the negative coordinate axes slightly more prominent.
Various minor bug fixes and improvements.
The HD 10180 sample simulation has been moved from the Abstract Systems folder to the new Exoplanet Systems folder.
The Gliese 876, Kepler 9, and Upsilon Andromedae sample simulations have been added to the new Exoplanet Systems folder.
The Comet Hartley 2 sample simulation has been added to the Solar System 2 folder.
The brightness of the Projectile sample simulation has been reduced to make it look correct, as in AstroGrav 1.8.2 and earlier.
The magnitudes of planets and major moons in the Solar System sample simulations has been improved by changing their colors.
A "beep when finished" checkbox has been added to the Evolve / Evolve To... dialog.
A bug has been fixed that could cause a highly eccentric orbit (such as Comet McNaught's) to be inaccurately displayed.
A bug has been fixed that could cause unwanted orbit lines to be displayed with a highly eccentric orbit (such as Comet McNaught's).
The algorithm used to calculate the magnitude of a non-luminous body has been improved.
The installation of AstroGrav has been simplified on Windows Vista and Windows 7.
Table column selectors are now focusable, so that column selection can be done with the keyboard.
On view windows, the negative coordinate axes have been made slightly more prominent.

New in AstroGrav 1.8.3 (Sep 1, 2010)

New in AstroGrav 1.8.2 (May 11, 2010)

Orbit Calculations:
A smaller object is no longer shown as orbiting a larger object when it is too far away to be retained in orbit for long.
A smaller object is no longer shown as orbiting a larger object when it is really just passing close by. [Eg, near-Earth objects.]
Complex multi-level object structures are replaced with simpler structures with less levels.
There are less orbital discontinuities visible during evolution.
The calculation of orbits has been significantly speeded up in most situations.
The above changes in no way affect the way that simulations evolve. Only the calculation of orbits is affected.
Units:
A Units... button has been added to the general preferences, allowing you to specify your own default selection of units to use in place of the SI units.
A Default Selection button has been added to the Edit / Units... dialog, allowing you to change a simulation's units to the default selection of units defined in the general preferences - much faster and less error prone than having to change each unit individually.
A bug has been fixed that caused an undo of a change to a time step unit (made with the Evolve / Settings... command) to be ignored.
Sample Simulations:
The 'Planets, Moon' and 'Planets' sample simulations have been corrected, because in version 1.8.1 the objects were shown at their locations on 22/12/09 instead of 01/01/10.
The orbits of moons 2003J4 (Jupiter) and Tarvos (Saturn) have been corrected in the 'Solar System' and 'Planets, All Moons' sample simulations.
Minor corrections have been made to the sample simulation notes, both in the simulations themselves (viewed with Edit / Notes...) and in the corresponding documentation.
The non-English sample simulations now have their notes (viewed with Edit / Notes...) translated to the appropriate language, instead of appearing in English.
Other Improvements:
A bug has been fixed that caused version 1.8.1 to crash when opening a simulation with a table that was last modified with version 1.6.3 or earlier.
A bug has been fixed that caused an undo of an evolver settings edit made during evolution to sometimes not work.
A bug has been fixed that caused double-clicking on a Mac data file to result in the startup preference activating as well as the file opening.
The Edit / Add Child... command has been improved to not add the new object to the system until after the dialog has been accepted.
The algorithm used to set the brightness of a new View window has been improved to take account of the number of luminous particles.
Several minor speed improvements have been made - primarily on Windows.
There are major improvements to the quality of the Italian translations of menu items, button names, text labels, messages, etc. Thanks to Danilo Attard Barbini from Rome for providing these.

New in AstroGrav 1.8.1 (Dec 18, 2009)

New in AstroGrav 1.8 (Oct 21, 2009)

Model Window Commands:
The View / Show / Auras command has been replaced with the four new commands in the new View / Object Style menu. These give you a choice of four ways of displaying objects instead of just the two.
The View / Show / Objects command has been added, allowing you to suppress the display of the objects if you wish. This may be useful if you want to study the changes in orbits without being distracted by flashing objects after each time step.
The View / Show / Inverted command has been added, allowing you to invert the colors on the display, so that black becomes white, blue becomes yellow, etc. This may be useful if you want to print screenshots without wasting a lot of printer toner or having to use a separate application to invert the colors.
In addition to these new commands, the View / Show / Data command has been removed, with the data now being permanently displayed on the status bar.
Date and Time Units:
The Time unit has been split into separate Period and Date/Time units, so that you can now specify different units for the period and the simulation date/time.
The Date/Time units now includes a Date + Time choice which replaces the old View / Show Time as Date command.
The Date/Time units now includes a Date choice which allows you display dates in the format 'AD 2010 Jan 01.234567'.
Tool Bars and Palettes:
Tools that are specific to only one type of window have been moved to separate tool palettes which take the the form of small windows that can be moved about by dragging their titles bars.
Tool palettes can be shown or hidden using the new View / Show Tool Palette command.
Tool bars are now the same across all types of windows, so that the View / Customize Tool Bar... command now affects all windows rather than just windows of one particular type.
A tool bar will no longer 'wrap', but instead displays a >> icon when there are too many tool buttons to display. When clicked on, a popup menu is shown allowing access to the 'overflow' commands.
A Search box has been added to the right of each tool bar. This provides the same functionality as the Edit / Find... command, but is quicker to access.
The default set of tool buttons has been expanded and improved.
Preferences:
Version 1.8 of AstroGrav includes new preference settings allowing you to specify the positions of tool bars and status bars if you don't like having tool bars at the top of windows and status bars at the bottom of windows. Tool bars can be positioned at either the top, left, bottom, or right of windows, and status bars can be positioned at either the top or bottom of windows. Each of the four different types of windows can be configured separately, so that (for example) you can have tool bars at the top of model windows and at the left of tree windows if you desire. If tool bars are positioned at the left or right of windows, the new Search box will be suppressed.
Other Improvements:
The size of the Windows download has been significantly reduced.
The terminology used for the different types of windows has been improved, with Model windows now being called View windows, Tree windows now being called Structure windows, and Detail windows now being called Object windows.
Several different custom cursors corresponding to the different key modifiers have been added, in order to make navigation less error prone.
The graphics display has been speeded up in most cases.
The View / Show Status Bar and View / Show Tool Bar commands now only affect the frontmost window, rather than all windows of the same type.
Changing the language preference now updates the About and Navigation Guide windows as appropriate.
The documentation and tutorial have been updated to reflect all the new and improved features.

AstroGrav Changelog

What's new in AstroGrav 5.1

New in AstroGrav 5.0.1 (Oct 30, 2023)

New in AstroGrav 5.0 (Oct 9, 2023)

New in AstroGrav 4.5.3 (Aug 25, 2022)

New in AstroGrav 4.5.2 (Jul 17, 2022)

New in AstroGrav 4.5.1 (Jun 16, 2022)

New in AstroGrav 4.5 (May 23, 2022)

New in AstroGrav 4.4.3 (Dec 7, 2021)

New in AstroGrav 4.4.2 (Oct 13, 2021)

New in AstroGrav 4.4.1 (Sep 7, 2021)

New in AstroGrav 4.4 (Aug 6, 2021)

New in AstroGrav 4.3.1 (Feb 1, 2021)

New in AstroGrav 4.3 (Jan 25, 2021)

New in AstroGrav 4.2.2 (Oct 11, 2020)

New in AstroGrav 4.2.1 (Oct 6, 2020)

New in AstroGrav 4.2 (Aug 21, 2020)

New in AstroGrav 4.1.1 (Jan 15, 2020)

New in AstroGrav 4.1 (Dec 23, 2019)

New in AstroGrav 4.0 (Jul 4, 2019)

New in AstroGrav 3.7.1 (Jan 4, 2019)

New in AstroGrav 3.7 (Nov 20, 2018)

New in AstroGrav 3.6 (Apr 12, 2018)

New in AstroGrav 3.5.1 (Dec 27, 2017)

New in AstroGrav 3.5 (Dec 9, 2017)

New in AstroGrav 3.4.3 (Sep 1, 2017)

New in AstroGrav 3.4.2 (Aug 4, 2017)

New in AstroGrav 3.4.1 (May 17, 2017)

New in AstroGrav 3.4 (Dec 17, 2016)

New in AstroGrav 3.3.3 (Jul 29, 2016)

New in AstroGrav 3.3.2 (Apr 25, 2016)

New in AstroGrav 3.3.1 (Apr 2, 2016)

New in AstroGrav 3.3 (Mar 4, 2016)

New in AstroGrav 3.2.1 (Dec 23, 2015)

New in AstroGrav 3.2 (Nov 26, 2015)

New in AstroGrav 3.1.1 (Sep 29, 2015)

New in AstroGrav 3.1 (Sep 16, 2015)

New in AstroGrav 3.0.6 (Jun 25, 2015)

New in AstroGrav 3.0.5 (May 8, 2015)

New in AstroGrav 3.0.4 (Mar 20, 2015)

New in AstroGrav 3.0.3 (Feb 13, 2015)

New in AstroGrav 3.0.2 (Dec 19, 2014)

New in AstroGrav 3.0.1 (Oct 29, 2014)

New in AstroGrav 3.0 (Oct 1, 2014)

New in AstroGrav 2.2.3 (Jun 11, 2014)

New in AstroGrav 2.2.2 (May 12, 2014)

New in AstroGrav 2.2.1 (Feb 19, 2014)

New in AstroGrav 2.2 (Nov 27, 2013)

New in AstroGrav 2.1.2 (Aug 29, 2013)

New in AstroGrav 2.1.1 (Jul 26, 2013)

New in AstroGrav 2.1 (Jul 1, 2013)

New in AstroGrav 2.0.2 (Dec 27, 2012)

New in AstroGrav 2.0.1 (Nov 12, 2012)

New in AstroGrav 2.0 (Aug 7, 2012)

New in AstroGrav 1.9.4 (Dec 10, 2011)

New in AstroGrav 1.9.3 (Oct 24, 2011)

New in AstroGrav 1.9.2 (Jul 4, 2011)

New in AstroGrav 1.9.1 (Mar 31, 2011)

New in AstroGrav 1.9 (Mar 19, 2011)

New in AstroGrav 1.8.4 (Oct 30, 2010)

New in AstroGrav 1.8.3 (Sep 1, 2010)

New in AstroGrav 1.8.2 (May 11, 2010)

New in AstroGrav 1.8.1 (Dec 18, 2009)

New in AstroGrav 1.8 (Oct 21, 2009)

New in AstroGrav 1.7.2 (Jun 12, 2009)

New in AstroGrav 1.7.1 (May 9, 2009)

New in AstroGrav 1.7 (Feb 3, 2009)

New in AstroGrav 1.6.3 (Nov 4, 2008)

New in AstroGrav 1.6.2 (Sep 5, 2008)

New in AstroGrav 1.6.1 (Apr 15, 2008)

New in AstroGrav 1.6 (Jan 15, 2008)

New in AstroGrav 1.5 (Dec 4, 2007)