Version 4.3 - 23rd January 2021
The following information is intended for existing users who are already familiar with AstroGrav and want to quickly find out about the main changes.
Version 4.3 of AstroGrav is an upgrade containing a large number of improvements and bug fixes. It is a free upgrade for customers who have already purchased a license for AstroGrav 4, so that all you need to do is to download Version 4.3 and use it in place of your old version. If you have any problems with this new version, please don't hesitate to contact us so that we can help you out.
Version 4.3 of AstroGrav has the following new and improved features.
Ephemeris Generation
Version 4.3 of AstroGrav includes the following updates to generating ephemerides with the Tools / Generate Ephemeris... command.
- A Refraction checkbox has been added to an ephemeris window, so that refraction can be taken into account when calculating the horizontal coordinates.
- The data displayed in an ephemeris window is now correctly updated whenever there is a change made to the Planetary Aberration, Refraction, or Use JNow checkboxes.
- The data displayed in an ephemeris window is now correctly updated whenever the viewing location is changed using the View From... button.
- The Window / Duplicate command is now available on an ephemeris window, so that it is now possible to duplicate an ephemeris window, change the viewing location of the duplicate, and then see side-by-side ephemerides of the same object from two different locations.
- After reopening a simulation with ephemeris windows, the reopened ephemeris windows now appear exactly the same as when they were saved.
Dates and Times
Version 4.3 of AstroGrav includes the following improvements to the handling of dates and times in solar system simulations.
- Dates and times in solar system simulations can now be displayed and entered with milliseconds.
- Errors involving the distinction between Barycentric Dynamical Time (TDB) and Coordinated Universal Time (UTC) have been removed.
- The Proleptic Gregorian Calendar is now used throughout.
- The AD and BC labels can now be switched off in the preferences. When switched off, the years before 2 AD are labelled 1, 0, -1, -2, ..., and when switched on the years before 2 AD are labelled 1 AD, 1 BC, 2 BC, 3 BC, ..., so that for example, the year -480 corresponds to 481 BC.
- The entry of dates has been made more flexible, in particular by making the entry of months case insensitive.
- Coordinated Universal Time (UTC) units have been changed to Barycentric Dynamical Time (TDB) throughout the sample simulations.
Trajectories and Histories
Version 4.3 of AstroGrav includes the following improvements when drawing the trajectories and histories of objects.
- The View / Trajectory Size... command has been renamed the View / Trajectories... command, and now includes a choice of what trajectories and histories are drawn relative to.
- There is now one trajectory size per view window instead of one trajectory size per simulation, so that different view windows in the same simulation can now have different trajectory sizes.
- A bug has been fixed that made it impossible to show trajectories or histories with a fixed background star or when viewing from a background star.
View Windows
Version 4.3 of AstroGrav includes the following improvements to view windows.
- Redshift and blueshift effects have been added when View / Show / Planetary Aberration is switched on, although these are only noticeable with velocities that are a significant proportion of the speed of light.
- Several minor corrections have been made to the planetary aberration calculations when View / Show / Planetary Aberration is switched on.
- When the viewpoint is floating, the status bar now just displays 'Viewpoint: Floating', with the coordinates of the viewpoint being shown in the associated popup message.
- A bug has been fixed that could cause angle, distance, and MOID labels to be displayed in the wrong place.
- Minor bugs have been fixed and performance improvements made to the drawing of grids.
- A bug has been fixed that could cause a new view window to appear blank, because it had been set up looking in the wrong direction.
- Moving the viewpoint to the fixed object now automatically changes the fixed object to the system barycenter.
Other Improvements
Version 4.3 of AstroGrav also has many other minor improvements and bug fixes, including the following.
- A greatly improved precession model has been added. This provides accurate precession for 200,000 years either side of the present time, which will be useful to those wishing to use AstroGrav for archaeo-astronomical purposes.
- A bug has been fixed that caused evolving to an event with the Evolve / Evolve To... command to run extremely slowly in some situations.
- The solar system sample simulations have been updated to the start of 2021, with the addition of the Kuiper Belt Objects named 2012 VR128 and 2013 JW63.
- Particle choosers have been changed to show at most 1,000 objects in the popup menu, because performance degrades significantly beyond that.
- A bug has been fixed that caused the tool palette of a new view window to be wrongly positioned.
- The default directories for the various types of file have been improved.