One of my favourite things to do on a clear winter night is to take a trip to a beach near where I live and do some amateur stargazing, far from the glare of streetlights. After years of simply using my eyes, I recently bought a portable telescope. Now I can just about see the stripes of clouds on Jupiter, which is a truly awesome sight. But I'm no expert, and to help me understand what I can see in the sky, both by eye and by telescope, I rely on my phone and its apps.
One of my favourite astronomy apps is Starmap, $5 on iOS. The main feature of this app is its virtual sky display. This is a re-creation of the sky above you, calculated from your GPS coordinates. It shows you where the stars, moon, planets and other heavenly bodies are. This display rotates and pans as you move your phone, so you can hold it up in front of you and figure out what stars or galaxies you're looking at. You can zoom in for more detail if you find something interesting, and tap on a planet or a star to see details about it. The display can be switched to a night mode, which turns the graphics red so as not to spoil your night vision.
It's elegantly designed, and the display is easy to read. Starmap excels in its extra features, which are useful even if you're an astronomy novice. Clicking on the "tonight" icon, for example, brings up a list of the best things to look for in the sky that night. This could include a suggestion to look at the moon's craters, a note that Jupiter is bright right now or a reminder to watch a meteor shower. You can limit this list to things you can see with the naked eye, in case you don't have a telescope. The app even tells you the weather and probable viewing conditions for the evening.
The one minor annoyance I've found with the app is that if you accidentally tap the screen, you disable the automatic movements of the star display. Alternatively, you may prefer The Night Sky Lite, free on iOS and Android. This app works in much the same way as Starmap, but the way it displays stars, planets and constellation shapes is simpler. This could appeal to beginners.
The app also has a section where it reports the "latest news" about sky events, but the data is mostly text and is probably best perused at home rather than in the field.
One great feature is the "share my sky" button, which lets you share a screenshot of your display of stars by email, Facebook or Twitter. The free Lite version doesn't contain data on stars or planets and lacks a night vision mode on iOS, but these features, as well as the ability to identify passing satellites, are included in the full version package, which costs $1.
On Android, another free option is Sky Map. This app uses Google's free star data, and its display acts as an interactive sky guide just as the other apps featured here do. It's simple to use and intuitive: Tapping on the screen brings up a menu that lets you switch on or off features like the lines in constellations, a representation of the horizon on the screen, and planet and star names.
Sky Map also has a neat trick to help you find a particular star. A graphic ring is displayed on screen over the star field, with an arrow on its edge that points in the direction of the star you are searching for. As you follow the arrow and spin your phone to line up with the star, the ring gets brighter until you've found your target.
But I found the app's sky display jittery on my Nexus 7; the stars on screen twitched a lot in response to the slightest movement of the tablet.
And if you're looking for an app that will teach you about all of the objects in the sky, Sky Map may not be for you.
Pocket Universe, a $2 iOS app, is packed with extras like a virtual walk on the moon and even star quizzes, and it speaks the names of stars or planets that you line up in the displayed cross hairs. I found its graphics cluttered, however, and potentially distracting.
Take care to avoid tripping, as I did the last time I used one of these apps at night (I was too busy looking up).
You can now insert yourself into that iconic James Bond "gun barrel" opening scene thanks to the free iOS app Skyfall Gun Barrel and its Android counterpart, Skyfall 007. The apps are really a promotional push for the DVD release of "Skyfall," but they create an entertaining clip starring you as Bond. ... The Sandbox is a new game on Android that blends pixel art and creative game play, and may remind you of Minecraft. It's free. (Kit Eaton/The New York Times News Service)