Copyright, using screenshots etc.
If you want to use screenshots for publications, videos, presentations etc., this is fine in principle for non-profit productions if credit is given. However, some of the images and textures used by Stellarium are copyright by others, and may require separate attribution or copyright/use clarification with the original authors. There was a lengthy discussion:
The README file in the program folder contains all known credits, references and special licenses for images and data.