Star Walk 2 for iOS Suffers a Myriad of User Interface Flaws

Star Walk 2 by Vito Technology is the next generation of the venerable sky charting program that was launched in 2008. This iOS app has been well received throughout the years, but the new release suffers from too many user interface and usability errors, and its does not fare well compared to the competition.


The Positives

According to Vito Technology, Star Walk 2 is completely redesigned, faster and smoother, and has a cleaner interface. And so, there are positives for this app that should be listed.

  • New simpler and cleaner interface in vibrant colors for retina displays.
  • Atmospheric visual and sound effects, stirring soundtrack.
  • Exclusive handcrafted artwork for constellations, inspired by minimalist low-poly art.

Looking southwest on Sep 8. Milky Way is shown reflecting in water.

Notable in this release is the appearance of 3D models of planetary nebula, constellations, comets, asteroids, and man-made satellites. This allows the user to, for example, see how a constellation looks from other locations in our Milky Way galaxy.

The pedagogical value here is good because the student is introduced to the idea that the appearance of the constellations is created by our unique perspective due to the Sun's location in the Milky Way. However, when looking at the back side of a constellation, it's not clear exactly where or how far one really is. So it's a qualitative feature.

Another good features is "Real-time motion tracking." According to Vito Technology:

As you hold your phone up and point it towards the sky, Star Walk 2 follows your motions using the built-in gyroscope to match the map on your screen to the stars seen from your location. Easily find any star, constellation, or satellite in the sky by tapping Search. Star Walk will indicate the direction to look in.

I do like the background music. It's inspiring, but I surmise it will get tiring after awhile. I had to turn it off to concentrate on the astronomy aspects of the app.

Finally, I liked spectrum bar on the left. If you turn it on, you can elect to see the sky in different wavelengths, for example, gamma ray, X-ray, visible, infrared and so on. The idea here is to teach the user that our eyes see only part of what's in the sky, and this is why we use various kinds of telescopes and different detectors on those telescopes.

The Negatives

During my review process, I found more than just a few interface issues that made for either a difficult time or created a disappointing experience.

1. The only horizon Setting, when not set to off, is a body of water. There are no options for say a wooded scene or a desert. Plus, there's no way to insert a horizon profile of your own location. While the liquid horizon makes for a snazzy reflection of the constellations when shown as mythical figures, competing apps, like Sky Safari, offer a richer selection of horizons.

A water horizon has artistic effects, but there should be
other options.

2. In the Settings, there is a slider for the visual magnitude cut-off for the sky. Unfortunately, there is no numeric value assigned to the slider setting. So, for example, if one wanted to simulate the sky at a specific location, say, Kitt Peak National Observatory in Tucson, AZ with 7th magnitude skys, there's no way to dial-in a specific magnitude. Vito Technology responded, "The scale we have is made specially for non-astronomers thus it is made like a slider to make the use of it easier. However we can think of how to make it useful for the Pro's as well." .

Settings are sparse. Cut-off magnitude not provided as numeric value.

3. The time slider on the right side allows one to easily change the date, depending on whether the year, month, day or hour is tapped and highlighted. However, if you've selected an object for inspection and leave the object selected, sliding the time bar makes the horizon jump up and down unexpectedly. That could be confusing to a new user. Also, one can easily get into a mode where the sky dances around too quickly, based on the operation of ther slider. That needs to be fixed.

4. Another UI problem I found was that if the user is inspecting the sky at a certain date and time, and the compass icon is touched in order to invoke a view of the current sky, there is no way to return to the previous view without repeating the previous setup. The same applies to Search. Vito Technology said, "This function is also not available yet. If we consider it as a good idea we can add it in the future releases."

5. There is no way to make the ecliptic appear. One workaround is to pick a planet that's visible, tap it, and the path of the planet will appear as a curved line.  But that fails to be instructive because it doesn't reveal that the other planets don't travel exactly on the ecliptic.

6. There is a serious inconsistency in the format for dates. In Sky Live, for the moon, the convention is DD.MM.YYYY. But the top header for the date in Sky Live is DD MONTH YYYY. Yet, on the main display of the sky, the app uses YYYY.MM.DD.HH.MM One would expect a consistent format, say European, and then perhaps a Settings option for the U.S. Vito Technology responded:

[Regarding] the regional format it should be the format you use on your phone. If it is European it should be European, if it is American, it should be American. As we see now it is a bug that we're going to fix. As for the way it looks in Sky Live, it is used this way because under the Moon phases there're not enough space [but] there is enough space for the longer date format.

7. Another major UI snafu, and this is severe, is that there is no setting to make sure stars brighter than a given visual magnitude are always labelled on the sky at a given level of zoom. The result in Star Walk 2 is that without such a setting, some brighter stars are not labelled because of the constellation labeling and text congestion while dimmer stars do get labelled.

For example, in the screen shot below, Altair (in Aquila) is labelled but not Vega (in Lyra), yet Vega is brighter in visual magnitude by quite a bit. (0.03 vs. 0.76). Only if one zooms in does the label for Vega appear, but then one loses the wider perspective of the sky.

Altair (in Aquila) not as bright as Vega (in Lyra), yet labelled.

8. Another UI snafu is the coloring of the "back" control on Live Sky. If a user goes to Live Sky first and isn't familiar with the convention for the controls, it's easy to lose it in the glare of the Sun in the upper left hand corner. The result is serious frustration about how to exit that mode. Making the control more visible against the Sun would avoid potential frustration.

In App Purchases

In my view, an introductory sky chart program should be complete in itself. That's because, even though this app may not be designed for the serious amateur astronomer, it is intended to be educational. And so asking for money to provide technical completeness is unworthy of the technical and educational motivation.

Educational items that should be included cost extra.

It would be like selling a chess program such that when one tries to promote a Pawn to a Queen, one must make an in-app purchase to have two Queens on the board.

I recognize the value of inexpensive apps in order to attract customers, but given that Vito Technology already has a strong following, the company should have enough self-confidence now to charge a fair price for excellence in the app.


There is an eight page guided tour available from the menu, but there is no higher level documentation from within the app. The 22 page PDF manual is available on the Vito Technology website, and while it's fairly good, it does have some oversights. For example, in item #1 above, there is nothing to explain the restricted options for the horizon setting.

Excerpt from PDF manual.

One can, of course move the PDF manual over to iBooks on the iPad, but I've seen many other iPad apps that take the extra trouble to include documentation within the app. One is SkySafari.

Comparison to the Competition

The developer's answers to my questions suggested that Star Walk 2 is intended more for K-8 education and familiarization. Serious amateur astronomers or those who are looking for a more advanced sky chart program will probably want to look at SkySafari, previously reviewed by TMO. The basic version of SkySafari is also $2.99.


Star Walk 2 is a clean and beautiful introduction to the sky, especially for newbies of all ages and young students. It's inexpensive, easy to use and fairly instructive. However, because it is a first version of a re-write, it has many UI issues to be corrected. And there is no in-app documentation or astronomy tutorials. Finally, the needy in-app purchases detract from the scientific and educational focus of this app, and that may steer some towards SkySafari, an app that delivers greater excellence with a range of price options to suit the user who grows in knowledge and experience.

Product: Star Walk 2

Company: Vito Technology

List Price: US$2.99



Inexpensive, easy to use, clean design, 3D mode, introductory tour, inspirational music, atmospheric effects, real-time motion tracking, attractive artwork for constellations, shows sky in various wavelengths. Universal app for iPhone and iPad.


Many UI glitches, limited settings including only one horizon (water), frequent insufficient labeling in sky and settings, no in-app documentation, in-app purchase required for full capability.