With phones now taking on more and more of the duties usually associated with fully-fledged computers, phone 'apps' have become genuinely useful aids for a variety of activities including astronomy. In this blog piece I've highlighted three applications for Google Android devices that have great content and prove to be a great help, whether you are observing with the unaided eye or with a telescope. Also, there are many fantastic astronomy applications for other phones. Feel free to add any of your own suggestions in the comments below - our team here at the Royal Observatory Greenwich will also be contributing. Enjoy!
Google Sky MapPrice: FREE
By far the most popular Android astronomy application, Google Sky Map provides a virtual window to peer into space. If your phone has a built-in compass, the application can display the sky wherever you point your phone! Sky Map also has a manual mode to drag your finger across the sky. Stars, constellations, deep sky objects, planets and the Moon are all displayed for your current time and location. Recently, the "Time Travel" feature has been added to see what the sky looks like for any time in the past or in the future. If you're looking for something in particular such as a planet or galaxy, you can search for it, and a pointer interface will guide you to your target.
Moon WidgetPrice: FREE
This no frills app gives you the most important information about the Moon at a glance. Adding this widget to your phone will give you a discrete image of the current phase of the Moon and times for Moonrise and Moonset. Having an application like this helps plan for a nights observations. If the Moon is coming up to, or is in, its full moon phase, then waiting until moonset comes highly recommended. By tapping into the Moon Widget some more detail is given about the Moon's current location, distance and how many days into the lunar cycle it is. As a preparation before a night of stargazing, this is a great addition to your app collection.
Just as we use longitude and latitude to mark our location here on Earth, there are equivalents for the night sky so that astronomers around the world can find their chosen target. The coordinates are called Declination (Dec) and Right Ascension (RA), but to make them useful for observing, some calculations are required. WhereIsIt makes the whole process pain-free by taking your current location and time, and converting Dec and RA to altitude and azimuth. Altitude tells you how far up from the horizon you should be looking or pointing your telescope. Azimuth tells you how many degrees (clockwise) around from North to look or aim. If you have the coordinates for your target, you can manually input them or you can select from a list of bright celestial objects including stars, galaxies and nebulae.
There are many more Android astronomy applications that could be mentioned in more detail here, but just try searching for "Astronomy" in the Market and see what you can find! For reviews of some of the top iPhone astronomy apps, check out this month's edition of the Sky at Night magazine and don't hesitate to contribute to the comments section below! Also, check out the Royal Observatory Greenwich facebook page here for the latest info on events and astronomy news!