Archive for August, 2009

CitizenSky Workshop and VStar Software

August 21, 2009

I attended the CitizenSky Workshop at Adler Planetarium in Chicago from August 5th to 7th 2009. CitizenSky is a collaboration between the American Association of Variable Star Observers (AAVSO), amateur astronomers (or “volunteer astronomers”, as one participant suggested) like myself, professional astronomers, and educators to encourage more of the general public to get involved in Science, to become “Citizen Scientists”.

The focus of the workshop was to communicate the fundamentals of variable stars and the observation of such objects (and of one star system in particular) to participants who could then take what they had learned back to their local schools, astronomical societies and other groups. The particular star of interest is Epsilon Aurigae, a strange variable star system that undergoes an eclipse every 27 years that lasts for about a year and a half. You can find out more about Epsilon Aurigae and the ongoing campaign to study the imminent next eclipse from the CitizenSky website.

It’s not an ideal object from South Australia. In mid-December it will be about 11 degrees above the northern horizon in the late evening, and that’s about as high as it gets from Adelaide. Use a program like Stellarium to determine its visibility from your location, e.g.

Epsilon Aurigae (circled) from Adelaide, South Australia, 19 Dec 2009 at 10:30pm
Epsilon Aurigae (circled) from Adelaide, South Australia, 19 Dec 2009 at 10:30pm CDT

On the last day of the workshop I demonstrated the latest revision of VStar, an open source, multi-platform (courtesy of the Java programming language) variable star data analysis application I’ve been developing since early May this year. This software is intended to be an easy-to-use variable star data visualization and analysis tool. The initial motivator for VStar is the CitizenSky project.

It all started as the result of a conversation I had with Arne Henden, Director of the AAVSO at the 2008 National Australian Convention of Amateur Astronomers (NACAA) in Sydney. I asked him the same kind of question I ask most astronomers I get the chance to talk with: is there any astronomical software you need developed? I have developed free software (e.g. ACE BasicPICCLIBothers) since 1991, but for a long time I had been looking for a way to apply my software development experience to benefit of the Scientific Community in my spare time. On the one hand I have an interesting and challenging software engineering day job, while on the other, I have a need to do something more than just contribute to a company’s bottom-line.

Arne said that they wanted to do a Java version of an old Visual Basic tool called VStar. This tool is referenced in AAVSO’s online tutorial material, but AAVSO wanted to replace it with a newer version that could be targeted at multiple platforms, not just Windows, in addition to adding new functionality.

Arne, Aaron Price and I corresponded after NACAA and talked about a number of projects including VStar. Initially AAVSO made the decision to develop VStar internally, but several months ago, we started corresponding again and I took it on as a volunteer effort. AAVSO provided Sara Beck as liason, and for the last few months, VStar has consumed my spare time and lead me to appreciate the benefits of energy drinks. I’ve communicated often with several other AAVSO staff and they’re a friendly and encouraging crew, in particular, apart from Sara, Arne, and Aaron: Richard ‘Doc’ Kinne, Matthew Templeton, Rebecca Turner, and Elizabeth Waagen.

VStar is still very much a work in progress but is being implemented in phases starting with basic features such as:

  • input from a the AAVSO International Database, AAVSO download and simple file formats;
  • light curve and mean plots;
  • individual observation inspection;
  • printing, saving.

Much of the above exists and is usable now. There’s a bug list in the project SourceForge tracker that I’m working on currently.

Next will come phase plots, period analysis algorithms, and the intent is to have a plugin architecture so that new algorithms can be added by anyone. Full functionality should be available by around March next year in time for another Citizen Sky workshop at which analysis of data on Epsilon Aurigae will be the focus.

There are no formal releases yet (since VStar is not mature enough yet), but you can download the “bleeding edge” trunk of VStar anytime, or you can download more stable tagged versions. Here are some download options:

To download the latest Vstar archive (tarball):

  1. http://vstar.svn.sourceforge.net/viewvc/vstar/trunk/
  2. Click “Download GNU tarball”

To download the latest VStar via Subversion, issue this command from a shell or DOS prompt, or use a graphical Subversion tool such as TortoiseSVN.

  • svn co https://vstar.svn.sourceforge.net/svnroot/vstar/trunk vstar

To download a specific frozen (or “tagged”) version such as DEV-17Aug2009 (a post CitizenSky workshop version, before new major changes), use a command like this:

  • svn co https://vstar.svn.sourceforge.net/svnroot/vstar/tags/DEV-17Aug2009 vstar

In each case, the top-level ReadMe.txt file tells you what additional Java libraries to download, where to get them from, and where to put them. I would like to include these on the SourceForge site as part of the download, but we’re still trying to determine the legality of that for each library.

Then it’s just a matter of running a batch file or shell script as described in the ReadMe file.

Ultimately VStar will also be available as a Web Start ™ application on the AAVSO web site. Parts of it may also be used as Java applets on the AAVSO web site.

There is plenty left to do. Testers are always needed, so feel free to help out with that. Michael Umbricht, another CitizenSky participant has done a lot on that front already. He is also keen to improve the currently sparse documentation and write tutorial material. Please let us know if you would like to help with testing, proof reading, or if you would like to get involved in some other VStar development activity.

I look forward to the next several months of VStar development!

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