Sky Guide, a star and constellation guide for iPhone is a brilliantly simple and intuitive app that adds a fun new dimension to stargazing for all ages.
Sky Guide’s conceptual model perfectly aligns with the mental model of stargazing. Although Sky Guide provides no instructions when opened for the first time, users can instantly infer what to do. Once the app is opened, the user simply has to hold the phone in the direction they are looking to see what stars, constellations, and planets are in front of them. As the user and their iPhone change directions (left or right, up or down) Sky Guide moves with them. However, Sky Guide has not constrained its use with the act of actually moving the iPhone around. If they prefer, users may also hold their iPhone still and simply swipe around the sky with their finger to get the same effect without having to physically move themselves or their phone around at all.
Both of the methods of stargazing with Sky Guide described above are excellent examples of natural mapping (i.e., taking advantage of physical analogies and cultural standards for immediate understanding). Like a camera, Sky Guide can work by moving and aiming the iPhone towards the section of the sky users are looking at. Similarly, Sky Guide can also work by the user swiping around the sky much like they would a map in the Google Maps or Apple Maps apps.
Sky Guide also makes its affordances very clear, i.e., if something in the app looks like it can be selected for more information, it can. For example, if a user points their iPhone in the direction of a constellation, Sky Guide will overlap that constellation with its name, lines connecting the stars of that constellation as well as an an image of what that constellation represents. The user is then able to click on that constellation and pull up a page for more information. Furthermore, the user then also has the option to either go back to the sky or read through the description and possibly click one of the links to another constellation, star, planet, galaxy, etc. These links are always visible and made obvious by being blue whereas any non-linkable text is white.
Besides the links described above, Sky Guide has also made its other features appropriately visible without keeping them on screen permanently. When initially opening the app, and whenever users touch the screen, a search link (identified by the universally recognizable magnifying glass icon) and a link to the app’s settings (an icon of 3 horizontal lines, which are easily recognizable for iPhone users) appear, but if the screen is not touched again the links will simply fade back out until the next time the screen is tapped. Again, because of Sky Guide’s excellent conceptual model users instantly know how to interact with these two functions because they are familiar to any iPhone user.