Thanks for your replys to my initial mail (see below). Kstars handbook http://kstars.sourceforge.net/handbook is availabe according to the following terms:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts.
I guess, that leaves us with the most freedom desired, right? I'll import one article of Kstars Astroinfo into Wikipedia, add a line about where this article originates from and ask John Harris, the author of Astroinfo, if that's OK with him. I hope, he'll answer this time...
To be in compliance with the GFDL, Wikipedia is, like the Kstars handbook, supposed to have the above license notice (1). It should also have a GFDL:History page, where it should list the "title, year, authors, and publisher" of Kstars Astroinfo, and a hyperlink to the downloadable version of Kstars Astroinfo (4.I, 4.J).
-tc