Comment 1 for bug 890608

Fix committed as revision 5020 to the trunk branch:
http://bazaar.launchpad.net/~stellarium/stellarium/trunk/revision/5020

May need some additional work: the existing function populating the button label was re-used, but it also loads star catalog data, which may slow down the translation or cause a bug when language is changed during a download. More testing is needed!