KStars is a desktop planetarium that is part of the KDE desktop environment, or it can be run on any other desktop provided you have the standard KDE libraries installed.
The first time you run it, KStars asks for your location, either from a list of cities or in latitude and longitude, which you can usually get from a GPS/SatNav device or from Google Maps (right click on your location and select What's Here). With that information, it displays a map of the night sky as seen from your location at the current time.
You can choose which objects are displayed and search for specific stars or planets, right-clicking on an object gives more details and links to telescopic photographs of it. Dragging the mouse changes your angle of view, or you can select an object and have it always centred in the window. You can also change the display to show the sky at any time, future or past, and have it run a time-lapse animation of the sky, showing the movement and transit of the various objects. You can also bring up a list of the objects that will be visible tonight
This is more than a toy for the curious, KStars has the ability to control a digital telescope, even remotely over the Internet. Whether your interest in astronomy is casual or serious, or anywhere in between, KStars provides a useful, interesting and fun window on the night sky.
Please note: KStars wouldn't launch on our Windows 10 system, complaining about a missing OpenSSL SSLEAY32.DLL file. To fix this, we went to the OpenSSL wiki Binaries page, chose the indy.fulgan link , scrolled to the bottom of the page, downloaded and unzipped the latest x64 build, and copied ssleay.dll and libeay.dll to the same folder as KStars.exe. A hassle, but it fixed the problem immediately.
A very useful and professionally presented, yet still fun, astronomy tool.