C2A : Realtime Free Planetarium Software for Windows

C2A is a free planetarium software for Windows that allows the user to build a detailed view of the stellar fields. C2A or CAA is an acronym of Computer Aided Astronomy. It supports a large number of known catalogues of the outer space objects. It comes with some of these catalogues while others can be downloaded from the internet. It can also be connected to your telescope for automatic navigation.

Even though not necessary but if you have Python 3.9 or higher installed on your Windows PC, some features of C2A will work better. Since C2A is a 32-bit application, it detects only the 32-bit version of Python. You can install Python even after installing C2A.

C2A has a cleverly designed user interface. It displays the view of the sky as displayed from the Earth. On the side there is a search bar in which you can search for any object in the sky. You can also choose from a number of available catalogues which should be used for searching. Upon discovery of a object we can center the sky map on that selected object. We an also zoom in or zoom out from this sky map.


If you have an advanced telescope that supports connection to the computer via a cable, then you can control it using the C2A software. It supports ASCOM connections as well as controllers such as Native LX2000, Astro-Physics GTO, Celestron NexStar, Gemini Pulsar, OnStep, AudeCom, PicAstro, Skysensor 2000 PC, and more. Once you have connected your telescope with C2A, you can search for any object in C2A and it will rotate the telescope in its direction automatically.


C2A is an advanced software for monitoring the objects in the sky. It can be used both by beginners and advanced astronomers. And if you have a compatible telescope then you can enjoy watching a new object located many light years away from us every day.

You can download C2A from http://www.astrosurf.com/c2a/english/.