STELLARIUM: A STAR AMONGST PLANETARIUM SOFTWARE

Stellarium's astronomical object search facility.

Many people with 3G mobile phones and portable media devices such as Apple‟s iPod have been amazed at the quality of applications, especially those relating to astronomy and navigating your way around the night sky. Most of my colleagues who are not amateur astronomers have hours of fun with these planetarium "apps‟ for their devices. However, the software for computers pre-dates that for mobile devices by many years and it is much more substantial, effective and interesting.

The astronomy planetarium software genre for use by the general public dates back to the early 1990s with the release of ground- breaking programs such as Redshift. Excellent though such early software was, the applications available were limited by the technology of the era, and pale into insignificance by the plethora and quality of the substantial applications available today.

When it comes to planetarium software for both the PC and the Apple Mac there‟s a huge choice of capable programmes on offer including Imaginova‟s Starry Night in all its various incarnations, United Soft Media‟s Redshift, Sky X, SkyMap and Cartes du Ciel (Star Charts).

The bad news is that although these products come complete with bells and whistles and are used by amateur and professional astronomers alike, they‟re not free, and in their various editions can cost anything from £30 up to £200. In addition these heavyweights have unnecessarily high hardware requirements. Starry Night in its professional editions requires at least 2GB of RAM and a fast dual core processor. It also claims a massive slice of valuable hard drive space real estate.

As usual, the internet comes up trumps yet again with a highly capable free alternative, Stellarium. It is used in professional planetariums worldwide and is GPL desktop software which renders realistic skies in real time with openGL graphics software. The software allows you to see what you can observe with the naked eyes, binoculars or a small telescope.

Downloading Stellarium from its website at stellarium.org is a breeze. The program is available for all main formats i.e. Windows PC, Mac, Ubuntu or Linux. At just 57MB for the Windows version, the program, unlike much commercial "bloatware‟ downloads in thirty seconds on a broadband connection, and the easy installation will be complete on even the slowest machines within a few minutes. Stellarium displays the astronomical target, in this case M33 in its real time position against the background stars. The program executes in seconds and you‟re initially greeted by the opening location scene.

Stellarium displays the astronomical target, in this case M33 in its real time position against the background stars.

At this point it is probably advisable to click the location icon and enter the name of your town or city or grid reference. Remember that this is real time software, and to hide daylight simply toggle the atmosphere icon. And without any more ado, your cosmic voyage begins. Just open the search box and type in M33 (the available predictive text will help), for example. Initially Stellarium will show you a naked eye view and will show you exactly where in the night sky outside the object will be.

To place it in its proper position within the constellations you can toggle constellation art, labels and boundaries. If the object is below the horizon and is not available from your viewing location Stellarium includes a toggle icon to remove the ground and horizon. Once found it‟s just a simple task of going out into your backyard and using the accurate depiction of M33 in the night sky in Stellarium to find it in the identical-looking real thing above your head (light pollution permitting) with your telescope.

Of course, you will have already seen M33 at much more close quarters; Stellarium allows you to zoom in on an object either by the backslash key on your keyboard or via your mouse. Many of the beautiful images of nebulae, galaxies and planets originate from NASA and further downloads are available after the initial program installation; these include more stars and more and fainter deep sky objects.

Zooming in on the target, maximum magnification regarding M33 reveals this truly beautiful spiral galaxy, not visible from my home even with my 200mm Newtonian reflector due to the Triangulum Galaxy‟s low surface brightness, and of course Teesside‟s truly appalling light pollution. Zooming in on the target. High magnification regarding M33 reveals this truly beautiful view:

Unfortunately this object is not visible from my home location due to light pollution. The present version of the program is 0.11.3, and its capability if it was commercial software would be amazing enough; it‟s incredible when you remember its freeware. It possesses a default catalogue of over 600,000 stars, extra downloadable catalogues with more than 210 million stars; asterisms and illustrations of the constellations; constellations for twelve different cultures; images of nebulae (full Messier catalogue); realistic Milky Way; very realistic atmosphere, sunrise and sunset and the planets and their satellites Its user interface include a powerful zoom, time control, multilingual capability, fisheye projection for planetarium domes, spherical mirror projection for your own low-cost dome, an all new graphical interface and extensive keyboard control and telescope control by which Stellarium and your computer will give a suitably adapted computer „go to‟ capability.

In terms of visualisation, Stellarium offers equatorial and azimuth grids, star twinkling, shooting stars, eclipse simulation, skinnable landscapes, and now possesses spherical panorama projection. The program can be customised with a plug-in system adding artificial satellites in real time, ocular simulation, telescope configuration and the ability to add new solar system objects from online resources. You can add your own deep sky objects, landscapes, constellation images and scripts. I really can‟t recommend this freeware enough. It is up there with commercial packages such as Starry Night, but has the added bonus of being tightly coded, small and unlike such paid- for packages it can be considered in no way „bloatware‟ and has been produced in the best programming traditions.

It is constantly updated by a group of academics, professional astronomers and the European Southern Observatory, and access to the internet allows for a database of astronomical objects to keep even the professional astronomer busy for years. And free really does mean free, both Stellarium‟s website and the program itself are devoid of any adware, unwanted toolbars or any other internet nasties.

In summation then, a fantastic package that anyone with even a passing interest in the night sky should download straight away. The only criticism I can possibly level at the software is 16 that it is so detailed, so visually real that using it to explore the night sky may prevent you from venturing into your back garden with all the light pollution, freezing temperatures in winter, cloudy skies and dew on your telescope‟s mirrors and eyepieces.

System Requirements: Pentium III 800Mhz; Apple Mac 667MHz; Linux/Unix; Windows NT/2000/XP/Vista/7; MacOS X 10.3.x or greater; 3D graphics card which supports OpenGL; 256 MB RAM, (1GB or more required for the largest star catalogues).

Overall Verdict: ***** (out of 5)
Pros: Free, comprehensive, capable, better than much commercial software, tightly coded with limited hard disk space required.
Cons: So good, it may prevent you from observing the real night sky!

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