Linux Goodies

In Pursuit Of The Perfect O/S



Kstars, the KDE Project Planetarium Program

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The Erroneous Premise -- Linux Has No Astronomy Software

When I started using Linux some years ago I was at first disappointed that there didn't seem to be any astronomy programs, particularly planetarium programs. I'd grown used to a couple in Windows, and I used them for planning my observing sessions. I could see what Messier objects were up, if any of Jupiter's moons were soon to transit, etc.

I'm happy to say that I was wrong then, in that there were a few Linux products around. If fact, there were several, and there are even more and better products around today.

Use this custom search engine to find astronomy software for you system (try Linux astronomy):

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Kstars, the KDE Project's Planetarium Program

One program that I've only recently become aware of is Kstars, part of the educational software under the Linux KDE project. I've found that in many ways Kstars has features I like better than my previous choice.

Kstars is primarily a planetarium program, drawing an interactive map of the night sky that can be set up for any location on Earth. Stars are shown against a deep blue background, and relative magnitudes are indicated by star size. The following image is from a portion of a typical Kstars display.

Sample Kstars Screen

Kstars Screen Shot Segment

Kstars has Extensive Display Control

The magnitude limit of displayed stars can be adjusted. When the user zooms in to any section of the sky, fainter stars come into view. The magnitude limit of zoom stars can also be set.

A few catalogs of interesting objects are also available, including the Messier catalog and the NGC catalog. These catalogs can be selectively turned off and on.

The user can elect to have constellation names and lines also drawn on the screen, as well as have bright stars labeled. The Milky Way can be represented by either a simple outline, or by a lightly shaded region as shown in the previous illustration.

Solar system objects can also be turned off and on, including planets, comets, and asteroids. Magnitude limits for these objects can also be selected.

Various guides can selectively be turned on and off, including a horizon line and a line following the ecliptic. The horizon can also be set to a solid colored region to mask off stars not visible.

Kstars has Extensive Viewing Controls

Simply moving the mouse around allows the user to select the Cardinal direction and elevation of view. The scroll wheel on such equipped mice can be used to zoom in to particular areas of interest.

There are a number of short cut keys that aid in controlling the view. Just touching the n, s, e, or w keys move the view to North, South, East, or West for example.

Kstars is Great for Planning Viewing Sessions

Any current display can be printed if desired, and a simple white background can be chosen for the printed chart. Also, there is a night vision mode, where the labels and lines are drawn in a subdued red color.

Field of view circles for a few common optical devices are selectable. When selected, these circles adjust to the zoom level to always give an accurate indication of field of view. The user can define and name additional fields of view as desired. In the following image, the white circle represents the field of view of a common 7x35 pair of binoculars.

Kstars Showing Binocular FOV

Kstars FOV Indicator

You Can Let Kstars Control Your Telescope

Kstars is equipped with drivers for many popular telescopes that allow remote control. Once the proper telescope type is selected, an object of interest can be easily selected for tracking.

Right clicking on an object will bring up a pop up of options. One can view details about an object, a picture of the object, or select from a list of links for more information on the object.

Kstars is Extensible

The feature I find most powerful is the ability to add more links to the link list for any selected object. This makes Kstars extensible in ways beyond most other products.

For example, another product I use, Xephem, has a handy Jupiter viewer that shows the position of the Great Red Spot and the Galilean moons. Time can be stepped forward or back to see when these Jupiter features are in desirable positions. Xephem also has a Mars viewer that displays the portion of Mars visible to the viewer for any given time.

Kstars has a vertical line chart like that at left for displaying the positions of Jupiter's moons, but it doesn't display any information about the Great Red Spot, and the display is more difficult to interpret than the more visual version presented by Xephem.

Note that the actual Jupiter chart is larger in a Kstars display, but was shown smaller here for loading efficiency.

Because of the extensible feature of Kstars, I was able to locate good Mars and Jupiter Javascript viewers online, and simply added these links to the link lists of the respective planets. Now when I click on either of the planets in the Kstars display and bring up the pop up menu, I get not only the previous details and links for the the planet, but the additional Javascript links that I like.