If you needed an application in KDE to study starts, galaxies and constellations, here is a nice application that may appeal to you. KDE developer Samikshan Bairagya posted some screenshots of the progress he made with KStars. The images below shows a  feature he implemented. What's Interesting is it suggests stars, planetary objects, constellations and deep sky objects to the user.

Clicking on starx, you will get a list of interesting stars. Further if you select a star from there, you will get detailed explanations of that object. Shown below is the information shown when Venus is selected.

You can also view the next interesting object from the window.

Bairagya is currently working on dark-sky objects and implementing them on What's Interesting. Kstars in available in the repos or all major distribution.