There’s something both primal and humbling about looking up at the night sky and seeing the same constellations our ancestors saw, except now we have the luxury of exploring the final frontier right from our smartphones—no rockets or telescopes required.
I think astronomy apps are must-have tools for budding astronomy enthusiasts. They can automatically locate and identify planets and other objects, show your local star map, and apply augmented reality (AR) overlays on top of constellations to make them easier to locate and understand. All you have to do is point your phone at the sky.
There are also options better suited for seasoned stargazers. They assume you already know the basics and offer more robust functionality—like providing local and global coordinate information—and allow you to control computer-based telescopes from the app.
Update, 9/15/21: Checked content for accuracy. Updated Stellarium mobile link apps and pricing for Sky Safari, Stellarium, and Star Walk Kids.
There are a variety of astronomy apps out there, and each kinda does its own thing. All of the apps featured here show you constellations, yes, but it’s how they show them to you and how they make it useful (by giving a basic explanation to beginners or by providing exact coordinates that advanced users can input into their telescope, for example) that counts. Here are a few other things you should make sure your app has, and why they’re important.
- Easy to Use: Astronomy is fascinating but there is a lot of information involved. It can be confusing (or downright overwhelming) for beginners at first until they learn how to parse it, so it’s important that these apps be intuitive, well-organized, and able to provide assistance or helpful descriptions when needed. And for advanced users, important information needs to be available at a glance so you can spend your time staring at the stars and not at your phone.
- Robust, Accurate Charts: With the exception of apps designed for kids, the best astronomy apps show more than the basic contents of our solar system. They should be connected to large databases that can show you at least a few hundred thousand stars, nebulae, galaxies, artificial satellites, and other deep sky objects. They should also be able to track and show you their movements in real time.
- Object Information: It’s one thing to see asteroids or planets in the app. It’s another thing entirely to be able to click on one and see information about it in an instant, which these apps do. Some keep it brief, only telling you an object’s name and a quick blurb about it, while others provide more comprehensive information, including the object’s location, composition, mythology, distance from Earth, and so on.
- Night Mode: Dark mode is awesome, but when you’re stargazing, it’s all about night mode, which reddens fonts, buttons, and anything that isn’t black on your screen so that you can maintain your eyes’ dark adaptation while stargazing.
If you’re new to astronomy, Sky Safari (Free/Android, $2.99/iOS) is a great place to start. The app offers the standard night sky map with AR constellation overlay, as well as tons of helpful information about celestial bodies (including over 120,000 stars and hundreds of other objects) in its sleek and well-organized interface. I recommend toggling the app’s Compass option for automatic real-time tracking (so you don’t have to manually move it). You can learn more about an object by tapping on it, then on Selection, and Object Info; from there, you’ll see the object’s name and photo, as well as information about its appearance, mythology, historical observations, evolution, and more.
The coolest feature of Sky Safari is one that’s more fun than function: time travel. No, I’m not talking about Doctor Who or Marty McFly, but the app can show you an animated simulation of how celestial contents moved as you “travel” back through time. I let the app run for about 45 minutes on my phone and it went back past 45,000 B.C.E (and I’m sure it could go further). You can even toggle night mode and view the night’s expected astronomical events, like where to see planets or if the ISS will be visible. Sky Safari is a fun, immersive choice for beginner and intermediate stargazers alike, and it makes learning about space easy.
Star Chart (Free) is beautiful because it’s easy to use and has tons of cool features that are fun for novice astronomers of any age to use. Simply point your phone at the sky and move it around, and Star Chart will tell you what you’re looking at (even during the day). It pulls from a solid database of over 120,000 stars, all 88 constellations, and the entire Messier catalog of deep sky objects, so you’ll have plenty to look at.
The app’s coolest and most unique feature is that it supports voice commands, like “Look at Andromeda” or “Fly me to the Moon” (although no Sinatra, sorry), so you can explore the galaxy and see glorious 3D renderings of objects from your phone. You can also explore the night skies of the future and the past with the Time Shift feature (10,000 years in either direction), get information about any object in the sky simply by tapping on it, zoom in on beautiful pictures of things like the moon, and set your location to anywhere in the world to see what the night sky looks like from that vantage point. Star Chart is an impressive and robust free astronomy app.
When paying for an app, you expect it to be great, and Stellarium Mobile Plus ($19.99/Android, $13.99/iOS) does not disappoint. From the makers of Stellarium, the renowned open-source planetarium software, Mobile Plus gives you access to a powerful star map based on the Gaia DR2 database of over 1.69 billion known stars, all known planets and comets, and most known deep sky objects (from a catalog of over 2 million nebulae and galaxies—which is more than any other app offers.
You can see popular constellations (including those from other civilizations), spot planets, and track artificial satellites as they move across the sky. One of the features I like best about Stellarium Mobile Plus is its use of real, high-definition photos of the moon, nebulae, and galaxies, which you can zoom in on and enjoy in great detail.
In addition to being powerful, Stellarium also has an intuitive and minimalistic interface that’s there to help but stays out of your way when you need it to. Reddened night mode is there to preserve your eyes’ darkness adaptivity, and should you choose to use the app offline, you’ll still have access to a reduced set of data, with 2 million deep sky objects, 2 million stars, and 10,000 asteroids. It also shows hourly angles, declination measurements, and other location info advanced users need.
Stellarium also allows users to control their telescope via Bluetooth or Wi-Fi and lets you drive any GOTO telescope using NexStar, LX200, or SynScan protocols. Whether you’re new to astronomy or president of your local astronomical society, Stellarium Mobile Plus is a solid, robust, and easy to use star map app, and well worth the $10 it costs.
Stargazing is a fun way for kids to learn about constellations, stars, and planets, and get them interested in astronomy. Talk about a win-win situation! Star Walk Kids ($0.99/Android, Free/iOS) is designed just for kids, and its colorful interface is engaging and easy to use. Kids can delve into the cool educational videos about our solar system and read fun facts about space, or they can point their phones up at the sky and see all of the visible constellations. With fun sound effects, videos, images, and games, Star Walk Kids is entertaining and educational.