Sometimes in amateur astronomy, a computer and appropriate software can be a very helpful thing. Take for example the following case, which is very similar to my own situation right now. You haven't observed in weeks, due to being busy at work (and having no vacation days left), and you finally get a chance to go out to the telescope. Once you've got your fancy 'scope all set up, you realize the sky has changed drastically since last time you observed. A session planning software would make a great addition to your gear at this point. Maybe you're new to the hobby, or just fooling around in some spare time. Astronomy software can also help teach new observers about the most interesting night sky objects and how to find them. In the following article, we'll take a look at some commercial and shareware programs that can help you out when you're at the 'scope.
The software I personally use the most is called Stellarium. Stellarium is an open-source, cross-platform software. This means it is free and available for Windows, Mac, and Linux computers. This is also the reason I use Stellarium quite a bit. I run Linux on all of my own computers, so it is a major plus for me. Stellarium is good at projecting a lifelike sky on your computer screen. The constellations and objects are labeled, and there are many display options. It will also simulate eclipses, and there is a meteors option. Some planetariums even use Stellarium to render their shows. Displaying the sky is one of the few features of Stellarium, however. There are some scripts available for it that provide new features, but some of the features of commercial software are missing.
If you want some of the nicer features, however, you're going to want to invest in some commercial astronomy software. Such a software is a great investment in your hobby, as it will make your observing sessions more organized. You may even learn some new stuff! Starry Night is a program that works somewhat like Stellarium, but includes many more useful features. Starry Night is available in several different versions, ranging from beginner to expert. Starry Night Enthusiast Version allows users to explore a 3-D model of the entire universe, and zoom in on planets, stars, nebulae, and other objects. It even allows you to track space probes as they roam through space. Starry Night Pro Version adds the ability to plan viewing sessions. It also will allow tracking of artificial satellites (such as the space station) using any computerized telescope mount and an adapter. Now that is cool... For those of you into astrophotography, they also offer an AstroPhoto Suite that can organize and improve your imaging sessions. Starry Night software is currently on sale, so check it out while it lasts!
Also worth mentioning is a list of open source and free programs at Midnight Kite. On this page, there are many, many programs, each of which is specialized in doing one calculation or another. This page is definitely worth checking out. If you need a program or script for your observatory, its probably there. Sky and Telescope also offer some free programs, such as Mars Previewer II, Binoplan, Cool, Flex, and Sec. All of these programs perform specific tasks and are available here. I have personlly found the Mars Previewer II to be very useful in determining if you really did see that feature on the red planet's surface.
I hope this article has been of some help to you in organizing and improving your sessions with the help of computer software. Of course, this is only the tip of the iceberg, so to speak. Therefore, expect more software articles as I discover new pieces of software that can help you get more out of your observing time.