For the April 8th eclipse, mobile apps offer everything from weather forecasts to local circumstances. Here’s a review of eclipse apps that you might find useful on the big day.

Total Solar Eclipse Australia 2023
Gary Seronik

On Monday, April 8, 2024, a solar eclipse will sweep diagonally across North America. On the big day, would you like to know when the upcoming solar eclipse begins and ends in your hometown? How much of the Sun’s face the Moon will cover at maximum, and when that occurs? Maybe you’re on the verge of a decision to get yourself into the path of totality — would you like to know the quickest way to get there? Are you worried about remembering when to remove and replace your solar filters and wishing you could get a reminder at the appropriate times? Will you be stuck at work on April 8th and hoping to catch a live stream of the eclipse so as not to miss the event entirely?

You can find all that and more in a wide variety of apps for your smartphone or tablet. Some are specific to this eclipse, while others are more general and can help you explore past and future eclipses too. Most are available for both iOS and Android, though some are specific to one or the other operating system. Many are free, and the ones that aren’t free aren’t particularly expensive.

In the course of maintaining the Apps & Software page of the American Astronomical Society’s (AAS’s) “Solar Eclipse Across America“ website, I compiled a list of every solar-eclipse-related mobile app I could find. I’m sure I missed some, but the ones I found provide, in the aggregate, an amazing cornucopia of useful features.

I use an iPhone 13 Pro, so for this article I downloaded all the iOS apps on the list and played with them to see what they do and how they work. I wasn’t able to try out any Android-only apps, so for them I relied on what I could glean from the developers’ websites. In what follows, I describe some of the key features of eclipse apps and highlight products that I feel implement one or more of these features particularly elegantly.

Eclipse Circumstances & Interactive Maps

Totality app
The Totality app, courtesy of Big Kid Science and the American Astronomical Society, enables you to find the timing of the eclipse from any location on the map.

Many of the apps listed on the AAS website compute eclipse circumstances for your current location based on coordinates from your smartphone’s build-in GPS receiver. This information includes contacts times (the beginning and end of the partial eclipse and, in the path, the beginning and end of totality), usually in the appropriate local time zone, as well as the altitude and azimuth of the Sun at those times and at maximum eclipse. Sometimes additional details are tabulated, such as the “o’clock positions” of the contact points, as if the Sun’s disk were an analog watch face with 12 at the top, and the speed of the Moon’s shadow.

Another important piece of information is the percentage of the Sun covered by the Moon at maximum eclipse, sometimes given as magnitude (fraction of diameter), sometimes as obscuration (fraction of area), and sometimes both. For locations within the path of totality, most apps will also report the duration of the total phase of the eclipse.

What if you want to find the same information for a different location? Most apps let you ignore the current GPS reading and specify another location — such as the site from which you plan to observe totality — using either a pull-down menu of countries and cities, a search box, or an interactive map. It’s easiest to explore how the eclipse progresses differently in different places if you can just tap a spot on a map and pull up the eclipse circumstances for that location, and that’s what the apps listed here do. Another advantage to having such a map is that you can see the path of totality and where different cities and towns lie in relation to it.

*SkySafari is a full-featured planetarium program. To access the eclipse map and circumstances for any location, set the location, set the date to April 8th, and tap “Tonight” on the main menu.

Eclipse Simulations

Where does the Moon take its first bite out of the Sun? It’s easier to catch the instant of first contact if you know exactly where on the Sun’s limb to look. Many apps provide illustrations of the different stages of the eclipse from the location you’ve specified, enabling you to see how the Moon will move across the Sun relative to your local horizon and zenith. Some apps show the relative position of the Sun and Moon at each contact, while others run a short animation. Either way, you’ll know exactly where to watch the Moon ingress, and then later egress, the Sun’s face.

  • Eclipse Guide (iOS, Android)
  • One Eclipse (iOS only)
  • SkySafari Eclipse 2024 (iOS, Android); see the note in the previous section
  • Totality by Big Kid Science (iOS, Android)

Weather

Eclipse Run - eclipse weather
Eclipse Run, by Martine Habib, provides an interactive app that includes weather forecasts.

As the saying goes, climate is what you expect, but weather is what you get. Eclipse chasers will pay close attention to weather forecasts along the path of totality in the days leading up to the big event. Some eclipse apps include up-to-the-minute weather forecasts; set your location to see how things are shaping up for eclipse day. Of course, you could instead use a weather app, but I’m not aware of any weather apps that include forecasts specific to the path of totality.

Routes/Directions

You should have decided long ago to travel into the path of totality, but you procrastinated, and now it’s crunch time. What’s the quickest route to the center line of the Moon’s shadow? Several apps will show you, providing mileage, drive time, and in some cases, turn-by-turn directions. Of course, you could instead use a map app, but it’s nice to have driving info available from within the same app you’re using to find an ideal observing location.

Eclipse Run alerts you when you enter the path of totality, then tells you when you’ve reached the centerline. If you’re battling the Mother of All Traffic Jams on eclipse day, knowing you’ve crossed into the path could let you breathe a little easier — as long as the Moon’s shadow hasn’t already passed you by.

Audio Prompts/Reminders

The Eclipse App
The Eclipse App features a built-in timer as well as cloud forecasts.

A partial solar eclipse unfolds slowly, but within the path of the Moon’s dark shadow time seems to speed up during totality and in the minutes immediately before and after. So much happens so fast that it’s easy to forget something critical, such as when to remove or replace your solar filters or when to stop looking through magnifying optics because of the Sun’s imminent return. Several eclipse apps feature audible reminders of key events and what to do in response to them. That’s important, because you don’t want to be looking at your phone when you should be looking at the sky! Just make sure you enable notifications on your device.

Camera Control

A growing number of eclipse photographers use specialized software to control their cameras from laptop computers. This frees them up to watch the eclipse rather than spend all of totality looking through a viewfinder and clicking a shutter release. Now that smartphones are becoming people’s most-used cameras, and now that solar filters are available for these devices, there are apps designed to make eclipse photography easier with them. EclipseDroid automates your eclipse photography with a connected digital camera, while Solar Snap gives you manual control over your smartphone’s built-in camera.

Citizen Science

GLOBE eclipse app
GLOBE Eclipse is a temporary tool in the GLOBE Observer app that will help you document air temperature and clouds during an eclipse.

Veterans of total, annular, and very deep partial solar eclipses know that when the Moon blocks the Sun, it can have dramatic effects on the temperature, wind speed and direction, and amount of cloudiness in the sky. If you’re interested in helping scientists track these changes and understand the roles that local topography has on them, you can make observations during the April 8th eclipse and report them to a central database via a smartphone app.

Communities & Events

Some folks like to experience moments of awe by themselves, but others like to share the wonder with fellow humans. If you’re in that latter camp and want to experience totality on April 8th at an organized event — perhaps one that includes talks from experts, hands-on activities for kids, food and entertainment, and more — you can find such events all along the path of totality in the Great American Eclipse app. If you’re just hunting for communities in the path where you’re likely to run into hordes of other eclipse enthusiasts, use The Eclipse App.

Final Thoughts

No matter what you want to know about the April 8th solar eclipse, there’s an app that’ll tell you. I encourage you to explore all the apps on the AAS’s Apps & Software page in case any of them offer features not mentioned here but of particular importance to you.

You don’t need to pick just one! Some apps shine at advance eclipse planning, while others are most useful on eclipse day itself. Since most cost nothing or at most a few dollars, try as many as look appealing to you. You’ll quickly zero in in your favorites. My favorite general-purpose eclipse app is Totality by Big Kid Science, which is now part of the American Astronomical Society’s product line, which also includes Sky & Telescope and Willmann-Bell books. You’ll notice that it appears several times in this article, because it does many things very well.

Clear skies to all on April 8th!

Rick Fienberg served as Sky & Telescope’s Editor in Chief from 2000 to 2008, then spent 12 years as Press Officer of the American Astronomical Society, S&T’s publisher since 2019. On April 8, 2024, he’ll experience his 15th total solar eclipse. This article is an updated version of the one he wrote for the August 2017 U.S. solar eclipse.

Find more information and resources for the 2024 solar eclipse.

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2024 total solar eclipse

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