Freeware Planetarium Software Review 2013
(This review is for amateur astronomers of the occasional or moderately serious type. Advanced features such as dome control, ccd integration, telescope scripting control are probably better suited by commercial programs such as Starry Night and TheSky)

Celestia
http://www.shatters.net/celestia/
One of the better "Universe tour" type programs, fly out to the planets and fly around. Celestia is a great program to get you young ones enthused about the night sky.
Not a planetarium program for the amateur astronomer, but still worth wasting some time on a cloudy night.
Requires a modern pc to run adequately. The rating here only reflects its use as a planetarium, it would obviously score much higher if Universe visualisation software was being reviewed.
Functionality
Ease of use


Asynx
http://www.asynx-planetarium.com/
Dated interface,similar to hnsky but with less slightly functionality. Still a capable planetarium program at a good price (free).
Functionality
Ease of use

Cnebulax
http://www.uv.es/jrtorres/CNebulaX.htm
Not the prettiest or easiest interface, but it excels for charting deep sky objects, over a million in its catalogue. While being quite a difficult program, it is well suited for the more serious amateur, with more functionality than many of the the programs on this page.
Functionality
Ease of use

HNsky
http://www.hnsky.org/software.htm
Somewhat dated interface,but still easy to navigate around. The simple interface hides many advanced features that the amateur astronomer will find useful, the starfields as show enough labels to be provide practical navigation, without cluttering the scene.
HNsky also has quite a few addons, supplemental data, and advanced features (Such as ASCOM telescope control) to make it a contender for the serious amateur. The program appears to be under active development, with active contributions.
The full package has high quality images of the planets and deep sky objects.
In summary - Not the slickest interface, but still of considerable use to the amateur astronomer.
Functionality
Ease of use

Cartes du Ciel (Skychart)
http://www.ap-i.net/skychart/
http://www.stargazing.net/astropc/index.html
Open source, cross platform. Somewhat dated interface, but still functional for a modern computer user.
It isn't pretty like stellarium, but does have a number of more advanced features for the serious amateur that stellarium is lacking, such as telescope control, mirroring views, accurately setting field of view.
This program may well be worth checking out if you have been observing for a while and want to play with something a little more advanced than stellarium.
Functionality
Ease of use

Stellarium
http://www.stellarium.org
Probably the easiest to use of the free planetarium programs. It has a slick, functional interface, and is the only free software reviewed here that actually looks like it belongs in this century and not the last. Navigation is by mouse drag and zooming is by mouse wheel, which makes getting around easy.
It may lack some some advanced features for the serious amateur. No comet or asteroid database, no telescope control, and what may be a show stopper for some, no printing of star charts.
Stellarium has without doubt the best interface of any of these programs both for ease of use and stunning good looks, but it does require a modern pc to run adequately.
Functionality
Ease of use


There are several other freeware planetarium programs that may be of interest, but they have not been included here either because they have not been updated in some time, or do not seem to offer any improvement over the programs on this page.
Some of these are Home Planet , Star Calc , Celestial Maps

There are a few others that look quite good, I will look at when I have time, such as Sky Orb , C2A , Aladin

To look at commercial astronomy software, or just to support this review please click a link below