screenshot of terratime clock on Nexus 5

A clock with a twist: the face is partitioned into day and night, showing at a glance how many hours of each are remaining. It also shows sunrise, solar noon, sunset, twilight, moon visibility, and stars - all accurate for today at your current location. You can add the TerraTime Clock to your device's home screen as a widget, giving you at-a-glance access to its features - as well as the current time, of course.

The basic TerraTime Clock is an ordinary analog clock face, colored partially black (with stars) for night and partially sky blue for day. These show the hours of daylight and darkness each day, read from the clock's numbers, as the hour hand (the short yellow one) moves between them. Twilight appears as the gradient between the colors, while the rising and setting sun is shown at the correct time on the edge of the face. Solar noon is shown with a small midday-sun icon, whose distance from the edge of the clock indicates the sun's apparent altitude at zenith.

Partway between the center and the edge of the clock face is the current moon phase. Its position on the clock face shows the time of "lunar noon", when the moon is at its apex; if lunar noon doesn't occur on the current clock face, the icon will simply appear at the midnight location. When applicable, the crescent moon is also shown at the correct angle for lunar noon at your latitude. The pale line behind the moon icon shows the time period when the moon is visible in the sky; this line intersects the clock rim at moonrise and moonset.

screenshot of terratime map on Nexus 5

The stars on the night side of the clock are a miniature snapshot of the heavens for your hemisphere (northern or southern), though admittedly they're too small to show much detail. They are accurately positioned for your longitude and season, however.

The clock activity (shown left) also displays specific data for sunrise, sunset, and length of day and night, as well as moon phase, rise, and set. Tapping any of the moon data fields will open our Moon Phase Pro app, if installed.

The clock has options for a 24-hour mode which shows the entire day/night cycle for the current day, and which (in our opinion) is more pleasing than a conventional 12-hour clock. However, it does take a bit of mental adjustment when reading the time; the angle of the hour hand won't generally be what you expect for a given hour. Instead, you need to look at what numbers the hour hand is pointing near, and read the hour from there. Alternatively, you have the option of taking the numbers off completely, if you prefer a clean look.

The image to the right shows an example of the TerraTime Clock widget, which enables you to add the clock directly to your Android home screen. It's available in multiple sizes and is included with the app; for instructions and details applicable to you, please refer to the correct section below. Be aware that a few devices, notably the NOOK Color/Tablet and the Kindle Fire, do not support widgets at all.

Android 4.0+ (Ice Cream Sandwich, Jelly Bean, most KitKat)

Open the app drawer (usually an icon like this icon image), select Widgets, and scroll to TerraTime Clock.

Please be aware that Samsung has disabled resizable widgets from independent developers (like us) on most of their devices running Android 4.0. If you own a Samsung phone, you'll probably need to use one of the non-resizable widgets.

Android 3.1 and 3.2 (most Honeycomb devices), also Nexus 5

Long-press in an empty area of your home screen, select Widgets, and scroll to TerraTime Clock. All styles are resizable and scrollable.

Android 1.6 - 3.0 (Donut, Froyo, Gingerbread, and early Honeycomb)

Long-press in an empty area of your home screen, select Widgets, and scroll to TerraTime Clock.

Compass Mode

screenshot of terratime clock on Nexus 5

A variation on the TerraTime Clock is called Compass Mode, accessed through the app's Menu. It displays a live compass dial showing the direction to the sun and moon, as well as their rising and setting points. The face of the Compass uses the same color-coding as the Clock – sky blue for the region of the sky where the sun is above the horizon, and black (with stars) where it's below. The analogous information for the moon is shown with a thin gray line, again like the Clock.

A pair of small icons shows the current direction and apparent altitude of both the sun and moon. When either is below the horizon, their direction is still shown, with their respective icon and a color-coded arrow near the compass rim (as seen here with the sun). This same data is also available in the text fields surrounding the compass dial.

And naturally, Compass Mode uses your device's hardware compass to align its display with the real world. When you want to switch back to Clock Mode, just use the same menu item.

Be aware that phone compass hardware can sometimes get out of alignment, causing TerraTime's Compass display to be off by some amount. If this happens, you can recalibrate it by waving your phone in the air in the shape of a figure 8 a few times. And any case, remember that Compass Mode is no more accurate than the hardware in your device, which probably isn't perfect.