WorldWide Telescope could be regarded as Microsoft's direct competitor to Google Sky, but I wouldn't agree with that.

WWT does contain space imagery that enables you to observe starts, planets, constellations and other celestial elements without having to buy an expensive telescope, that's true. In that sense, it's similar to Google's space browsing tool. But in my opinion, this app is much more intended for professional astronomers – or at least serious astronomy fans – rather than for people who just want to take a sneak peek at our planet as if they were taking a ride on a NASA shuttle.

Don't get me wrong here: there's nothing wrong with being a serious astronomy app. I'm just warning you in case you expect something else. Other than that, WorldWide Telescope is a great tool that all astronomy fans are going to love. It includes loads of information and also lets you download guided tours from the program itself to learn more about a certain topic.

You can freely move around the sky with your mouse, but I found this a bit confusing and soon preferred to use the image galleries under the Explore menu. These galleries were a bit disappointing though, because you can perfectly see the boundaries of the image you're viewing and so it doesn't feel like a real telescope anymore.

Worldwide Telescope is not a space browser like Google Sky; rather than that, it's a comprehensive astronomy atlas with loads of data, photo galleries and freely downloadable guided tours.

Download WorldWide Telescope Beta in Softonic

If you're a big fan of the Solar System and staring into Space through your telescope, then you'll absolutely love OpenUniverse.

Open Universe is an exciting project that brings the Solar System to you - in realtime. Most similar programs simulate or recreate the solar system from static models but this program attempts to show you exactly what is going on at any one time. The program existing in a former state as Solar System Simulator (Ssystem) launched in 1997 and has expanded and advanced so much, that it's now come to encompass the entire universe. The word "Open" has been added to to encourage open source users to improve and enhance the project. This is a million times better than the Space Exploration option on Google Earth with highly detailed images of Earth and the planets. For example, you view the Earth from the Sun, zoom in and out and even zoom in on stars. It labels everything too so no more looking up in the sky and wondering what that constellation is. The graphics are not exactly brilliant - it's a bit block and some of the stars look like blobs of white ink. However as a learning tool, it's a brilliant little resource.

For space exploration fans and those that are trying to teach other about the Universe, OpenUniverse is an exciting and powerful project.

Download OpenUniverse 1.0 in Softonic

Staring at the moon has something romantic about it, doesn't it? But I'm not sure if staring at this virtual moon produces the same effect.

Moonphase is an astronomic tool that tells you exactly what the moon phase is at this very moment – or on any day you choose from the program's embedded calendar. It works with any location on Earth, which you can select by entering the correspondent latitude and longitude numbers or simply by clicking on the map (much easier, huh?).

Besides displaying the moon phase and using attractive animations to switch from one phase to the other when you change date or location, the program doesn't really offer much more: no configuration settings, no location search box. Well, at least you get the sunrise and sunset times as a free extra.

Moonphase is a simple astronomy tool especially developed for those of you who feel a special attraction towards our satellite.

Download Moonphase 3.1 in Softonic

SkyOrb could be defined as a domestic planetarium, a space simulator that enables you to travel around the Solar System without leaving the comfort of your computer.

The only downside to having a planetarium at home is that you're the one in charge of it. SkyOrb is not easy to configure, although you may as well leave every option as it is. In any case, some knowledge of astronomy is advisable, especially since the program doesn't include a help section.

The main space view window is quite intuitive: you can move around with the mouse and zoom in and out planets, satellites and other celestial elements, although it doesn't really show any more detail. Also, it feels awkward not to be able to zoom with the mouse wheel.

Download SkyORB 1.8 in Softonic

Celestia is a free real-time space simulation that lets you experience our universe in three dimensions. Unlike most planetarium software, Celestia doesn't confine you to the surface of the Earth. You can travel throughout the solar system, to any of over 100,000 stars, or even beyond the galaxy.

All travel in Celestia is seamless; the exponential zoom feature lets you explore space across a huge range of scales, from galaxy clusters down to spacecraft only a few meters across. A 'point-and-goto' interface makes it simple to navigate through the universe to the object you want to visit.

Download Celestia 1.5.0 in Softonic

It illustrates star positions of any instance of the day observed from any geographic locations on the Earth. The star positions can be viewed and presented as images of hemispherical whole sky or any of the user defined sub-areas. These images can be zoomed at different scales, rotated, screen-captured and printed. Also, StarCalc has many other functions of calculation and showing of sky objects.

This program is based on common "Plugin StarCalc interface to catalogs and object groups", which allows program to add new modules as Plugins. These modules enable the program to use astronomy catalogs support and many others add-ons down the road or directly from other vendors.

StarCalc has a simple interface, most operations are implemented by mouse. The program employees the WYSIWYG technology (What You See Is What You Get), which helps you to print a detailed image of any enlarged area of sky in its finest astronomical details.

Download StarCalc 5.73 in Softonic

This simple yet interesting software, provides you with everything you need to see what's going on in the night sky today. It also forecasts how the night sky will look like in the future, and can project predictions for thousands of years into the future.

Download Asynx Planetarium 2.20 in Softonic

Chances are that not very many people have heard of Stellarium although it is very similar to one of the most popular pieces of software available today – Google Earth. While Google’s software allows you to focus on the earth from a starting point in outer space, Stellarium reverses your perspective and places you at any point on the earth’s surface, staring up and out into deep space.

An interesting feature is that as time passes, the virtual star system will evolve, with the sun setting and the various constellations becoming more prominent in the dark night sky. You have a selection of visual effects that you can switch on or off such as the atmosphere, or trace lines for the star systems. Impressive stuff for a few minutes, but once you’ve got the general gist of what the software entails, you’ll quickly tire of zooming out to distant stars and watching as they slowly move across the screen.

While Google Earth brings you detailed photos of our planet’s surface, Stellarium can only achieve a much lower resolution representation of the solar system’s planets, without mentioning the fact that stars are limited to simple white dots zipping through the sky. With over 120,000 stars accurately plotted out in this virtual planetarium, it’s obvious that a lot of work has gone in to its creation. However, that excruciating level of detail is likely only to appeal to the real die-hard star gazers.

The idea behind Stellarium is a good one in theory, but when it comes down to it most people will see it as little more than a smart, interactive screensaver. That said, if you have an affinity for astronomy, would like to learn the constellations, or simply enjoy watching beautiful sunsets, then this is for you.

Download Stellarium 0.9.0 in Softonic

Solar Model 3D is a three-dimensional modeling system that recreates the movement of planets and satellites in the Solar System. It allows the user to speed up time and estimate the reality of moving and rotating planets and its satellites.

The program uses Irrlicht real time 3D engine for rendering and textures that resemble the surface of planets and satellites with a high degree of realism.

The speed of rotation and translation movements can be changed with number keys: one stands for a minute per second, two for an hour per second, three for a day per second and four for four months per second.

You can also click on any planet or satellite to obtain information about them and move aroud the universe with your cursor keys.

Download Solar Model 3D 1.1 in Softonic

NASA released World Wind six months before Google Earth, yet it failed to make as much of an impact. However, anything coming out of the prestigious American aeronautics administration is definitely worth a closer look. So what sets World Wind apart from Google Earth?

World Wind's real selling point is the quality of its satellite imagery. World Wind reveals Earth in many different perspectives thanks to the large variety of maps. Blue Marble exposes Earth in its true colors, Landsat 7 gives you high resolution imagery, and MODIS can display time relevant data such as earthquakes, fires or floods. Browse over mountains and observe the snowy peaks, the clouds, and the different colors of the rock, with incredible precision. Be aware though that the lower you go, the more detail will appear, and World Wind will take more time to process the image.

A digital globe wouldn't be complete without its own search option. Find a destination by typing its name in the search tool located on the top bar. Landmarks are particularly well catalogued. If you select the landmark finder tool from the top section, World Wind will exhibit small tags for all locations it considers of significance. Click on the tag and you will be directed to the Wikipedia page for that particular landmark, where you'll be able to read all about it. It is important to point out however that the search function in World Wind is not as good at finding cities as it is with landmarks.

Another of World Wind's assets is its usability. Zoom in over the map using the rollover button of your mouse and skim to parts of the screen with your mouse. The more you focus down on a place the more names of cities and significant locations pop up. These can clog up your screen however, so you'd be wise to configure World Wind to only show the information you need, like country borders and urban areas.

To set itself apart from Google Earth, World Wind provides two original tools. Capitalizing on its lunar explorations, the aeronautics administration lets you view the Moon in extremely high definition. Focus in on its craters, deserts and plains and search for Apollo 11's landing site. Additionally, World Wind recreates the infamous Oregon trail mapped out by American adventurers Lewis and Clark at the beginning of the 19th century, stretching out from Independece, Missouri to the Pacific state of Oregon. World Wind points to significant landmarks which should be of interest to students or history amateurs.

World Wind is as good a digital imagery program as Google Earth. While the image resolution process can be sluggish, World Wind manages to set itself apart thanks to its landmark finder and fun tools like the Moon visualizer and the Lewis & Clark trail.

Download NASA World Wind 1.3.5 in Softonic

Have you ever asked yourself where the Voyager space probes are? What does Saturn look like in Titan’s sky or, better yet, what does the rise of Jupiter look like from the surface of Europa? WinStars can help you find the answers to these questions.

WinStars uses the latest 3D technology to show the objects of our solar system in a realistic manner. Thus, it is possible to move from one planet to another, to follow a space probe on its long voyage or to observe a celestial event from a place to which you could never go.

The use of the Jet Propulsion Laboratory’s DE 404 planetary theories allows us to have a precise representation of the events displayed.

Download WinStars 2.076 R2 in Softonic

Solar System 3D Simulator is a FREE software application that generates a realistic solar system model and planets in 3 Dimension on the PC using advanced physics formulas. It can display the planets and their orbits, the sun and the moon.

The nine planets including planet earth and their detailed physical & chemical information and image pictures is also displayed including solar power, solar energy and solar eclipse details. The graphical output is in high-resolution 3D full color format and the orbit view can be adjusted and the orbits tilted & rotated to any angle. The speed of the solar system can also be varied.

The Solar System model is useful for learning about the physics of the universe, astronomy, science projects & science experiments interactively for both adults and kids. Students of Elementary, Middle and High School can use it for science fair projects ideas, physics help, science news & creating science articles.

The software is easy to use with a fully Windows based interface. The program has a fully graphical menu oriented interface designed for ease of use. The Solar System 3D software has been designed for fast setup and interactivity with excellent high quality visual output. The software runs on all Windows Operating Systems.

Download Solar System 3D Simulator 3.0 in Softonic