Using Open Source, Part 4: Celestia & Stellarium
by Doug Anger, Technology Columnist
Over the past three weeks, the Weekly Geek has been reviewing free open source applications in the OpenOffice suite. This week, we take a break from work-related software and continue our trek into the world of Open Source with a couple sky-watching programs: Celestia and Stellarium.
Unless you're in an astronomy class, neither of these programs is likely to help you with your next term paper, but if you have a scientific or inquisitive mind or just like stargazing, they will certainly help you to enjoy the beauty of the night sky.
Celestia is your 3D atlas of the universe. When you first open the program, you find yourself in space looking at either a familiar star called Sol, otherwise known as the sun, or a little blue and green planet called Earth. Press the enter key and start typing the name of your favorite planet, star, moon, et cetera. If Celestia recognizes it, it should appear in the list on the bottom of the screen. When you're finished, hit enter again. Then press g for go and enjoy the ride. With a decent graphics card, Celestia's 3D fly-throughs are impressive enough to wow even seasoned sci-fi aficionados.
For some of us though, flying through the galaxy and being able to see hundreds of thousands of stars, planets, and other objects in real-time just isn't enough. The folks who made Celestia anticipated this, so they also allow you to travel forward and backward in time. Say you missed comet Hale-Bopp back in 1997? Just go back to April 2 at about 11 PM and it's clearly visible in the northern sky. Granted, that's not as good as seeing the real thing, but it's pretty cool nonetheless.
If the particular outer-space object you are looking for isn't one of over a hundred thousand in Celestia's database, you can probably find it online at the Celestia Motherload. Follow the simple instructions to add it to your copy of Celestia and give yourself a pat on the back for being a real astronomy whiz. Also online are high resolution images of things that are already in Celestia to increase the image quality at close range. To see a demo of what Celestia can do, simply press the d key at any time.
Another open source sky-watching program is Stellarium. Stellarium can turn anything from a laptop screen to a planetarium projector into a view of the sky from Earth. While Stellarium doesn't allow you to fly through the galaxy in three dimensions, its renderings of the sky are far more realistic under many circumstances.
In Stellarium, you can look in any direction from any point on earth and go forward and backward in time. Use the time control in the lower right corner of the screen to watch the sun rise and set and track the stars and planets across the sky in real time, fast-forward, and rewind. You can show and hide drawings and names of the constellations, names of stars, planets, and nebulae, coordinate lines, the ground, and realistic atmospheric effects. The search tool lets you find out when, where, and in which direction objects will be visible in the night sky.
You can download Stellarium for Mac OS, Windows, and Linux free from http://www.stellarium.org/
Celestia is available, also for free, for Mac OS, Windows, and Linux at http://www.shatters.net/celestia/. Additional free models for Celestia can be found at http://www.celestiamotherload.net/.
Stay tuned for Using Open Source, Part 5 next week.
