VStar is a visualisation and analysis tool for variable star observation data developed in collaboration with the American Association of Variable Star Observers (http://www.aavso.org/) and the Citizen Sky project.

VStar can load observation data from files or the AAVSO International Database, display interactive light curves and phase plots, and perform period analysis.

Plug-ins allow VStar's functionality to be extended.

In order to run VStar, you need to have version 1.8 or higher of the Java runtime installed on your computer. For more, see:

• Oracle or
• Amazon Corretto

The dist directory contains the latest vstar.jar built from source so you don't have to build it (see below).

The file extlib/ReadMe.txt details additional Java libraries that are required (and should already be present as part of this distribution) to run VStar.

The data directory contains sample variable star data files mostly taken from the AAVSO International Database.

The easiest way to run the latest version of VStar is by clicking on the Java WebStart (TM) download button on the AAVSO web page Data tab (Data -> Data Analysis) or the VStar GitHub web site or the Citizen Sky VStar team page:

• http://www.aavso.org/vstar-overview
• https://github.com/AAVSO/VStar

The WebStart vstar.jnlp file can be saved (e.g. to the desktop) and used as an alternative to accessing VStar via the web site.

VStar can also be launched by one of the following methods:

• Mac OS X: double-clicking the "VStar" launcher application.
• Windows: double-clicking "VStar.exe" launcher application.
• Linux (or other Unix variants or bash users): running the "VStar.sh" shell script.

Each of the foregoing options runs VStar with the same memory allocation parameters as for WebStart, permitting, for example, larger datasets to be loaded. For running VStar locally, this is the best method.

If you downloaded a VStar distribution, you will find a data folder containing sample datasets.

If you started VStar via WebStart instead, the latest example data files are available here:

https://github.com/AAVSO/VStar/tree/master/data

To open a data file in VStar:

1. Select "New Star from File..." from the File menu.
2. Navigate to the data directory via the file dialog.
3. Choose a file, e.g. "eps_aur_2445000.csv". and plot views.

For more complete documentation, see the VStar User Manual.

This section is of interest to developers rather than VStar users.

The file build.xml is an Ant file used for building a VStar distribution jar file from source. This is not necessary if you just want to run VStar, only if you want to Ant can be downloaded from http://ant.apache.org/ and 1.7.0 or higher is assumed. Type "ant -p" to see the options.

The src directory contains the Java source code for the tool.

The most recent version of the source code may be obtained from the VStar GitHub repository at https://github.com/AAVSO/VStar

The test directory contains unit tests. For testing, JUnit 3.8.2 is assumed (http://www.junit.org). This is of interest to developers only. See also extlib/ReadMe.txt for more about testing libraries.

VStar is licensed under the GNU Affero General Public License, version 3. See doc/license or http://www.gnu.org/licenses/agpl-3.0-standalone.html for details.

For licensing and links to source code for the external libraries used by VStar see the included ./extlib/ReadMe.txt file.