Ringlord Technologies Products


StarCat is a star mapping tool capable of visualizing and allowing you to travel among tens of thousands of stars. It uses a custom 3D graphics engine and runs on any operating system capable of hosting a Java 1.6 or later JVM (runs great with Java 1.7)

As of April 2012 StarCat's development has refocused on Java for a number of reasons: First, although C++ and the Qt Cross-platform Application Framework made for a clean and responsive GUI, the better optimized 3D engine was actually slightly slower in C++; additionally, my lack of access to Mac OS/X, Microsoft® Windows®, *BSD, and other operating systems would have meant that StarCat is available only for GNU/Linux systems. I find that no more acceptable than a Windows-only or Mac-only tool.

At this time the Java version of StarCat is the only one available for you to play with. It's rather raw and incomplete, but should give you an idea where StarCat is headed. There are two ways to get a taste of this:

  1. Download the software (starcat.jar) as well as a star catalog (.sc.gz file) as shown in the blue box below. Ultimately that's the better way to run the software.
  2. Run StarCat directly from this page using the Java WebStart link provided. You'll always get the latest version that way, but the star catalog will be downloaded each time, so that's going to be slower. The biggest benefit to this method is the simplicity: One click does it all.

NOTE: In either case, you must have Java 1.6 (or later) installed.1

Screen Shots

Everybody loves screenshots, so I hope to put some up Real Soon Now™ For what it's worth, the image near the top of this page is a screen shot.


StarCat makes only a linguistic distinction between stars, planets, moons, asteroids, etc. In essence they are distinguished by the amount of energy they emit (stars emit energy, planets don't), what their surface looks like, and what kind of atmosphere they have. StarCat does not care that Pluto is small, dingy, and that it has a goofy orbit: Planet, Dwarf Planet, Ball of Ice, or Object of Intense Debate, for StarCat it's just a Satellite of the Sun.


StarCat provides a 3D view of the universe (the star systems you've loaded for display). You can roate the view, change the center of the view to any star, and zoom in & out. There is also a 2D sectional view of any given star system, with the system's bodies laid out in a line; some aspects of the system, mainly orbital parameters, can be manipulated directly in that view.

Arbitrary data can be attached to any system or body, including free-form notes, images, references to external data, etc. The idea is that StarCat can capture whatever data you want to keep. For those interested in maintaining fictional data, StarCat supports the creation of travel routes between systems, flexible travel times, and boundaries of influence to help map the boundaries of star-spanning empires.

Star Catalog

StarCat maintains all of its data in gzip-compressed XML files. No matter the future of StarCat, your data will always be available to you by way of uncompressing and perusing the human-readable XML.

Physical units (radius, mass, period of rotation, etc.) can be entered in Earth or Solar units, or in real-world measurements.


On a i7-920 computer with nVidia GeForce 9800GT graphics card and Java 1.7, StarCat can render almost 1 million star systems per second2. I've seen performance as bad as 10% of that on some systems; what JVM you are running, your CPU, and your graphics system will all be determining factors, so your mileage may vary as they say.

Note: An experimental implementation in C++ demonstrated no speed advantage whatsoever over Java in the 3D rendering department; only the performance of the GUI components was snappier with Qt.

Scientific Accuracy & Limitations

Although many of the computations are rooted firmly in science and what we know about the universe today, StarCat is not necessarily an expression of scientific rigour:

Product Download

Description:A star catalog and 3-dimensional (3D) visualization tool.
License:Free as in Beer
Requirements:Java 1.6+
Launch (web):Launch StarCat (1.0KiB) using Java WebStart
Launch (shell):java -jar starcat.jar
Download:starcat.jar (292.5KiB)
Documentation:sol.sc.gz (1.4KiB) (our solar system)
hipparcos10.sc.gz (17.5KiB) (183 stars w/in 10pc)
hipparcos25.sc.gz (135.9KiB) (1550 stars w/in 25pc)
hipparcos50.sc.gz (574.2KiB) (7059 stars w/in 50pc)
hipparcos.sc.gz (8.7MiB) (113711 stars)
Note: The hipparcos files are extremely limited extracts from the real thing and should NOT be used for any purpose other than loading into StarCat. My extraction software is still rather limited, and there are no guarantees that any of the data in these catalogs is accurate, complete, or useful in any other way. I'm serious!

Development Status & Future Direction

As of April 2012, the following reflects my hopes and aspirations, but as time has proven repeatedly, this schedule is likely to slip and slip again:

Version 0.4 (+3 Months)

Version 0.5 (+2 Months)

Version 0.6 (+2 Months)

Version 0.7 (+2 Months)

Version 0.8 (+3 Months)

Version 0.9 (+4 Months)

Version 1.0 (+1 Month)

Source Code?

Once the softwre is complete, StarCat will be released in source form, licensed under the GNU General Public License (GPL) Version 3; if you are itching to help out before that, drop me a line and I'll see what we can work out.


A definite inspiration for StarCat. If AstroSynthesis ran well on non-Windows® machines (i.e. under WINE), I might never have written StarCat. AstroSynthesis looks very nifty, and is certainly worth checking out!
Project Rho
Winchell Chung's superb collection of star mapping information, related mathematics, and links to a wealth of tools have been a great source of inspiration!
A totally cool universal planetarium tool. Orbit planets, check out moons, fly to other stars and nebulae. It rocks. Totally!
1  If you have an Oracle Database installed and you are running Microsoft® Windows® then it is possible that Oracle's Java 1.4.2 JVM is placed earlier in the program search path than the later (more modern) JVMs that you may have also added to your system. This would prevent StarCat (or any modern Java software) from running. It's beyond the scope of this document to help you fix the order of entries in your PATH variable, but you should be able to figure it out with the help of Google or whatever search engine is your friend.
2  If you are getting ridiculously bad refresh rates with your system, you might want to ensure that you are using a JVM with a good Hotspot implementation; some OpenJDK builds work well with normal GUI stuff, but have major performance issues with 3D.

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