The Night Sky In Your Pocket

Star Walk iPhone App Review   

Star Walk Title Screen

Download_on_the_App_Store_Badge_US-UK_135x40_0824If you want to learn about what you see up in the night sky, it used to be that you needed a paper star chart like this. Now however, you need look no further than your smartphone. One App in particular that I’ve been using for more than a year and still find immensely valuable is Star Walk released by Vito Technology. It’s a great little tool to help you find your way around the night sky and learn a little more about the objects you’re looking at. It’s also great for impressing your friends when you know that bright star is actually Jupiter.

Vito Technology offers Star Walk for iPhone and Star Walk HD for iPad. These are effectively the same app, so just pick the one for your device. The screenshots here are from the iPhone version.

Star Walk Facing South

First of all, Star Walk a beautiful app. You can see a lot of effort was invested to present a sky map that is a joy to interact with. If you take Star Walk out at night and point it up toward the sky, it will automatically orient itself to your location and the direction you’re facing. This makes it pretty easy to identify the stars you see in the sky with the stars displayed on the screen. As you pan around, the constellation will show up on the stars in the center of the display. Pinch-zoom your way around, and when you find an object you want to know more about, just tap on it to highlight it, then click the little green info dot to see more details.

Orion Nebula Orion Nebula Info

Note: The app does occasionally get a little confused about the device’s orientation and direction. This is generally easily remedied by spinning your phone around and lowering and raising it again.

Star Walk Sky LiveWhen you first open the app, it shows a summary page called Sky Live. This page in itself is a wealth of information on the amount of daylight, phase of the moon, and visibility of the planets. This is a handy at a glance reference, and is also accessible from the main menu.

The App also includes orbital data for many satellites, including the ISS, Hubble, and the Iridium satellites. The search screen is also hugely valuable for find an object you’re looking for, or just browsing the database of objects in the App. Faded text for an object indicates it’s below the horizon, which is a handy feature.

Star Walk Search

It’s worth noting that the data isn’t complete nor perfect. Particularly the apparent size tends to be missing for most emission nebula, which I find a little frustrating. Still, I’ve tried several other night sky apps, and Star Walk has by far been the best in terms of ease of use and ascetics. It also manages to make up for some of the data holes by integrating direct access to the wikipedia pages for many objects. The Wikipedia data can be slightly inconsistent with the data in the App for attributes like apparent magnitude, but the values are always in the same ballpark, and likely just represent different data sources.

Star Walk Night ModeStar Walk also includes a night mode, that turns everything red on black. This is a great concept, but in practice, the lack of contrast on the display makes it far less usable. I find myself instead just dimming the screen brightness as far as it will go and using the normal viewing mode. More interesting for skywatchers is the slider to change the time and date, which is great for figuring out something like when Saturn will be visible again, or to track satellite orbits.

The settings panel includes a slider to set the visible magnitude, that is to only show stars that are above a certain visibility. Unfortunately the slider doesn’t have any actual values to indicate what this actually means in terms of the magnitude scale, nor does it offer an indicator for naked eye visibility. Hopefully this is a feature the developer will improve on. I find that just setting this slider about 2/3rds of the way to the right works well for me.

There are many other interesting features in this app, but I think this provides a good beginning overview to help you decide if Star Walk is something you would enjoy.

Summary

Despite a few minor gripes, I use Star Walk regularly, and it’s well worth the current $2.99 asking price. This app brings the old paper star chart into the smartphone age, and makes exploring the night sky easily accessible to everyone. I highly recommend it.

Pros

  • Intuitive and beautiful interface.
  • Excellent for identifying visible objects.
  • Fairly deep database of objects.

Cons

  • Magnitude scale doesn’t show numbers, just a sliding scale.
  • App can get confused about the phone’s orientation.
  • Limited information on the planets (offered as a separate app).
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