I just went through the presentation of your planetarium software on
http://www.brockhaus-multimedial.de/planetarium/index.php, and it appears
that it quite obviously re-uses part of the open source software Stellarium,
as least for some data files and graphics.
The problem is that since Stellarium is released under an open source
license (GPL), you simply cannot re-use it without releasing your software
under the same kind of license and you certainly cannot omit to credit the
We therefore ask you to:
- credit the stellarium's team
- release your program under the GPL (or compatible license)
- provide an access to your source code (this is mandatory in open source
Note that our goal is not to prevent you making business using our work:
this is perfectly fine for us, and is compatible with the license we chose
for the stellarium (you don't have to pay us to use our code or data). But
you have to use an opensource license and provide your source code too, so
that any modifications you make to the project can be read and used by
others. The best for us would be that you contribute by yourself to the main
project by sending us patches to add the new features into stellarium.
Beside the fact that you have no choice to accept our claims, you will also
realize that this is usually a win-win strategy to work with us.
Fabien Chereau, project coordinator of Stellarium (www.stellarium.org) on
behalf of the Stellarium's team