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VOPlot Help


VOPlot is a tool for visualizing astronomical data from VO-India. It is run as a java applet. We are currently using an old version (V 4.1), but eventually hope to either update to a newer release or replace it with another program.

Application Blocked Error

VOPlot uses an unsigned jar file which can cause a security error with the latest versions of Java (i.e., Version 7). You may not see this with earlier versions of Java. The error message will look like this:

VOPlot Error Message

To overcome this error, the best solution is to add the MAST web server to the "Exception Site List" in the Java Control Panel. On a Mac, this is found in System Preferences -> Java. Click on Security then "Edit Site List". In the window that opens, click "Add" and type in the server name appearing after "Location:" (e.g., ""). Click "OK" to get out. (This should prevent the problem from occurring in both Firefox, and Safari, and will maintain the selected level of security for all other web sites.)

You may see other windows appear when VOPlot starts prompting you for permission to continue. In Firefox, you may want to check tools->add-ons and set "Java Applet Plug-in" to "Always Activate" rather than "Ask to Activate".

Note: Currently Java version 7 is not compatible with Chrome, so if you already have Version 7 installed, Chrome can not be used to run VoPlot. You can restore Java version 6 following these directions, or perhaps wait until a new version of Chrome becomes available.

Other Strange Behaivor

Sometimes VOPlot fails to complete the plot, or displays only a portion of the plot window. We have found that expanding the browser window andor clicking in the plot window can sometimes help the plot to appear.