Viewing the Night Sky with Linux, Part I: KStars

By: Akkana Peck
Thursday, August 28, 2008 12:22:45 PM EST
URL: http://www.linuxplanet.com/linuxplanet/tutorials/6521/1/

KStars, Your Celestial Tour Guide

What's that super-bright star in the western sky after sunset? Was the moon full last night? Is Mars visible now? What time will the sun set on Saturday?

Do you ever look up at the sky and wonder about it? Your Linux desktop has lots of astronomy programs that can help you explore the night sky. This article will start with the one that's easiest to use: KStars.

KStars is a nifty "planetarium program" that's probably available through your Linux distro. Don't let the "K" scare you off -- kstars works fine even if you're not running KDE.

When you first run kstars, you'll be presented with a setup wizard. Choose your city from the list, then move on to the Download Extra Data Files screen. KStars has lots of extra catalogs you can download, but getting them is a little tricky, because after KStars installs each one, it pops up a dialog underneath the "Get Hot New Stuff" window then waits for you to click OK before you can go on. Move the upper window aside to see the OK button.

Once in the sky view (Figure 1), you can drag the view around just like Google maps, and zoom in and out with the magnifying glass icons or with your mousewheel. The ground shows up as solid green, to help keep you from getting lost. If you want to get rid of the ground to look at something that's currently below the horizon, there's a button in the toolbar to toggle it off.

Exploring With Binoculars

If you want to learn the constellations or identify a bright star, KStars is just the ticket. Figure out what direction you're looking, then drag the KStars view around until you're looking in that direction. For example, the "S" in Figure 1 means I'm looking pretty much south. Then try to match the stars you see with the constellations shown in KStars.

Tip: if you find all the star names distracting, you go to Settings->Configure KStars, click on Catalogs and change the star catalog "For stars brighter than" from 4.0 to 2.0 (Figure 2).

Do you have binoculars? They're a great way to explore the night sky. Start with Jupiter (at the upper left in Figure 2, above Sagittarius). You won't have any trouble finding it -- it's the brightest thing in the southern sky for the next few months, though that's hard to tell from KStars. You can find other planets with Pointing->Find Object....

How many of Jupiter's four bright Galilean moons do you see? You can tell which ones are moons because the moons are all lined up. If you don't see any, try resting the binoculars on a fence or other solid support. A tripod mount is even better, if you have one. Now go back to KStars, center on Jupiter and zoom way in. Which moons did you see?

Leaving the Solar System

Moving outside our solar system, try for the Lagoon nebula in your binoculars. Search for it by name ("Lagoon") or by its Messier catalog number, "M 8", in KStars' Pointing->Find Object.... Be careful with spacing -- KStars isn't picky about capitalization but it does insist on the space after the "M". The Lagoon is in the constellation Sagittarius, which looks like a teapot; the nebula is the steam rising from the teapot's spout. Can you see the nebula in binoculars? It does sort of look like steam, a faint fuzzy smear -- not much like the Hubble Space Telescope picture of it. You can see the HST photo and lots of other views in KStars by right-clicking on the nebula.

There are some great star clusters nearby: M 7 in the tail of Scorpius is a good binocular target. Then see if you can find the fainter M 6 just above it.

One thing I love about KStars is its beautiful star views. Notice all the different colors? Stars really are different colors due to varying age, size and composition, from red Antares to white Vega. Try searching for "Albireo", then zoom way in to see an example of a beautiful double star where the components are two different colors. Seeing the two colors is easy in a telescope but difficult in binoculars. Albireo is easy to find, though: it's the southern end of the Northern Cross, or the eye of Cygnus the swan.

One more project. Try for something a lot farther away: the Andromeda galaxy (M 31). With really dark skies you can see it with the naked eye, but you'll probably need binoculars if you live near a city. That's a trillion stars you're looking at there ... a whole separate galaxy a lot like our own, but bigger.

There's plenty more to see. Try a web search for binocular astronomy, then use KStars to help you find each object. There are dozens of celestial objects you can see with binoculars, hundreds visible with a small telescope ... with a little help from your Linux desktop.

Akkana Peck is a freelance programmer and writer and the author of Beginning GIMP: From Novice to Professional.  She's also a long-time amateur astronomer.