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Version 1.9 - 17th March 2011

Version 1.9 of AstroGrav is an upgrade containing several significant improvements and bug fixes. This information is intended for existing users who are already familiar with AstroGrav and want to quickly find out about the main changes. This is a free upgrade for customers who have already purchased a license, so that all you need to do is download Version 1.9 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 1.9 of AstroGrav has the following new and improved features.


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

Version 1.9 of AstroGrav includes the following updates to the Solar System 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.


Version 1.9 of AstroGrav includes the following improvements to the way that units are handled.

  • 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

Version 1.9 of AstroGrav also has many other minor improvements and bug fixes, including the following.

  • 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.