Stargazing with a smartphone

Thanks to smartphone apps, you can now keep a wealth of astronomical knowledge in your pocket. We review some of the best available right now.

Your smartphone can be a powerful astronomy accessory during an observing session. Credit: iStock

By combining GPS positioning and an accelerometer, your phone can tell not only where you are on the planet, but exactly where you’re pointing it.


Cue planetarium apps that show you exactly what you’re looking at in the night sky.

There are apps to help you plan observing sessions, find satellites and the International Space Station.

There are apps that aid astrophotography, and provide the latest astronomical updates.

Below, we look at 15 of these essential tools for astronomy.

Practical aids

SkySafari 5 Pro

  • Price: £38.99
  • Platform: iOS/Android
  • Pros: Remote control of Go-To telescopes; extensive data; custom observing lists; red-light mode
  • Cons: Expensive; a huge app at 1.7GB; requires telescope accessories
  • Link:

01 - Sky Safari

No app goes as deep as SkySafari 5 Pro.

On its own it’s a great astronomy app: you can create observing lists, check celestial coordinates, get ISS/Iridium satellite notifications, view images from the Digitized Sky Survey, and even explore an intergalactic map of where an observing target is in the Universe relative to the Sun.

However, this app is both expensive, and huge in terms of file size.

Using it to remotely control a computerised Go-To telescope requires a separate adaptor to let the app communicate with the setup, which can cost several hundred pounds.


  • Price: Free
  • Platform: iOS/Android
  • Pros: Free app; excellent audio narration; accurate 
  • augmented reality overlays
  • Cons: Larger smartphones won’t fit in viewer
  • Link:

02 - universe-2-go

Of the many planetarium apps, there are few audio guides or augmented reality offerings that overlay information directly onto the night sky. This one is both.

For best results it should be used with a Universe2go star viewer (£79); insert a regular-sized phone into the casing and look through the viewer to see star names and constellation boundaries overlaid onto the real night sky.

Aim the virtual target at a specific object and an audio narration begins.

Without the viewer you can put the app into planetarium mode on a phone or tablet and hear the same audio.

Celestron SkyPortal

  • Price: Free
  • Platform: iOS/Android
  • Pros: Remote control of telescopes; audio tours in earphones
  • Cons: Brand specific; large app at 296MB; red-light mode
  • Link:

03 - celestron skyportal

Celestron’s SkyPortal can be used to wirelessly control models from both the brand’s NextStar Evolution line-up of Schmidt-Cassegrain telescopes, or with any computerized Celestron telescope when used with a SkyPortal Wi-Fi module (£120).

After an easy pairing and alignment process the app allows your phone to act as a wireless hand controller; tapping an object on the phone screen for your scope to centre in the eyepiece.

At its core is a great planetarium app, with four hours of audio commentary – and it’s available to download for free.

Scope Nights

  • Price: £4.99
  • Platform: iOS
  • Pros: Forecasts for specific locations; dark-sky advice
  • Cons: Forecasts not always accurate
  • Link:

04 - ScopeNights

Every amateur astronomer yearns for clear, dark skies, and this exhaustive app helps you find them. It presents a simple 10-day weather forecast for your GPS location alongside a rating for all-night stargazing (poor, fair, good, etc).

But it’s the ‘Scope Sites’ section that impresses most, allowing users to both save favourite observing locations and search for new ones.

It even includes locations where amateur astronomers are regulars, such as observatories and officially designated dark-sky sites.

Lastly, a dark-sky map allows you to see how much light pollution there is at a site.

Observing Aids

Stellarium Mobile Sky Map

  • Price: £2.99/£2.19/£1.49
  • Platform: iOS/Android/Windows Phone
  • Pros: Realistic views; red-light mode; light-pollution slider
  • Cons: Mostly technical data on stars
  • Link:

05 - Stellarium

This planetarium app from the creators of the original and free Stellarium computer software impresses by keeping it real.

As well as a virtual horizon, it has an option to mimic what you can see with the naked eye, and even a light pollution adjuster.

Overlays of the constellation lines, and equatorial and azimuthal grids can be superimposed.

There’s also an easy-to-reach red-light mode and an unexpected section on the star lore of other cultures, including Inuit, Navajo and Aztec.

GoSkyWatch Planetarium

  • Price: £3.99
  • Platform: iOS
  • Pros: Target-search; celestial grid design; red-light mode
  • Cons: Bright stars only; obvious and invisible planets are treated the same
  • Link:

06 - Go skywatch

This app for casual stargazers treats bright stars and planets like targets against a celestial grid view that remains the same whichever orientation you hold the phone.

A voice announces that you’ve found a planet.

Is Pluto a planet? You decide – there’s an option to choose ‘Pluto is Planet’ in the settings.

Announcing distant planets could be misleading since they’re impossible to see with all but powerful telescopes, but the app’s target search makes it a useful tool.


  • Price: Free
  • Platform: Android (iOS in development)
  • Pros: Simple design; accurate predictions; red-light mode
  • Cons: Only shows man-made satellites; adverts along the bottom
  • Link:

07 - Heavens-Above-skychart

If you want to find a man-made object in orbit, you’ve come to the right place.

Anyone wanting to see the ISS, a bright satellite or witness an Iridium flare probably already knows about the excellent Heavens-Above website; this app uses the same prediction engine to make calculations specific to your GPS position.

It does so in a basic but thorough manner, with a list of events visible that night, as well as a dedicated section for each genre of object.

Star Walk 2

  • Price: £2.99/£0.99
  • Platform: iOS/Android
  • Pros: Easy time travel; tablet version allows voice search; red-light mode
  • Cons: Detailed content requires an in-app purchase
  • Link:

08 - Star Walk 2

This beautifully designed app has a useful time travel mode: touch the clock in the top-right corner then drag a finger up the side of the screen and the night sky goes into fast-forward, at any speed you desire.

That’s useful for planning long (and future) observing sessions, as is the Sky Live page, which gives at-a-glance rise and set times for planets and the Moon.

However, detailed information on constellations, deep-sky objects, planets and satellites will all cost you extra.


Adobe Photoshop Express

  • Price: Free
  • Platform: iOS/Android/Windows Phone
  • Pros: Effective noise reduction
  • Cons: Fewer options than desktop version
  • Link:

09 - Photoshop

If you’re doing astrophotography or creating nightscapes using a camera with Wi-Fi, this app version of Photoshop makes a good stand-in for the desktop software so popular with astro imagers, letting you edit and check photos on the go.

Key features include sharpen, clarity and exposure sliders, but most useful is a clever noise reduction feature that automatically zooms-in on the image.

It also includes shortcuts to upload finished images to everything from Adobe’s Creative Cloud to social media.


  • Price: £9.99
  • Platform: iOS (Android in development)
  • Pros: Precise positioning for Sun; Moon and Milky Way
  • Cons: Complex interface takes some to get used to
  • Link:


10 - Photopills

Want to capture that iconic moonrise or moonset photo where our lunar companion glows orange as it hangs above the horizon?

PhotoPills can help by showing you when and exactly where the Moon will be at dusk on the day of the full Moon, so you can plan the shot.

Remarkably, it can do the same for the Milky Way, which makes PhotoPills unique.

There are some great advice and tutorials on the developer’s website.

NightCap Pro

  • Price: £1.99
  • Platform: iOS
  • Pros: Manual camera controls; records photos as TIFF files
  • Cons: Limited by your phone’s camera quality
  • Link:

11 - NightCap

Of the many apps that allow you to take images in low light conditions, NightCap Pro is the most astrophotography centred.

The app gives you the manual control to take DSLR-like nighttime photographs using a phone camera; presets include stars, the ISS and meteors; there’s even a star trails mode.

The ISO goes all the way up to 6400, there’s built-in noise reduction and an intervalometer for night sky timelapses, and it even records photos as TIFF files.

All that’s needed alongside it is a phone holder, a tripod, and clear skies.


Cosmic Watch

  • Price: £4.99/£3.35
  • Platform: iOS/Android
  • Pros: Creative design; encourages a new perspective on stargazing
  • Cons: Large app at 178MB
  • Link:

12 - Cosmic Watch

Time is not a number, it’s a precise position in space, as you’ll quickly learn from this stunning 3D app that’s both a standard world clock and an astronomical timepiece.

You look onto Earth from above your actual GPS location, and see which stars and constellations are overhead.

Meanwhile, the changing positions of the Sun, the Moon, the planets on their orbits, and even the shifting position of the Milky Way beyond are all integrated to create an app packed with detail.


  • Price: Free
  • Platform: iOS/Android/Kindle Fire
  • Pros: Live rocket launches on NASA TV; latest images from NASA missions
  • Cons: NASA’s ‘Astronomy Picture of the Day’ images are scattered through the app
  • Link:

13 - nasa app

Who can resist watching a rocket launch live? Mainstream TV channels rarely broadcast such launches, but it’s all on NASA TV, which you can watch through NASA’s app.

Highlights include uninterrupted and multi-feed coverage from launch pads, views inside the ISS and a live webcam outside the space station that’s pointed towards Earth.

The app also contains the very latest images from Curiosity and Spirit rovers on Mars, updates on all NASA space exploration missions, and more.

ESA on Flickr

14 - esa app

ESA is at the heart of all spaceflight in Europe. At the time of writing the organisation was between apps, but preparing to launch ESA InTouch.

Meanwhile ESA continues to regularly upload to photo-streaming app Flickr, sharing the latest images from its missions around the Solar System and behind-the-scenes photos.

The app is easy to navigate and photos are split into albums for each mission or theme.


  • Price: £2.99
  • Platform: iOS
  • Pros: Impressive animation; illustrations and music
  • Cons: Fact-hungry kids may get frustrated
  • Links:

15 - space app

Want to throw rocks at Curiosity?

You can with this well-thought-out space ‘playscape’ for kids, produced by some talented illustrators and animators.

It gives a valuable perspective on the Solar System and its planets through simple games and close-up views.

Designed for kids from four years old and up, it offers an interactive journey to the planets, their moons, and the Sun, but it’s all done through show and play.


There are no captions, no spoken words, just great animation and a suitably creative soundscape.