Purchase and Download

Map and Globe

Clock and Location



Purchase and Download

My payment was accepted but I can't download the app. What should I do?

We receive a lot of support inquiries about purchase and download problems, but unfortunately, there's very little we can do about it. The individual stores selling the apps are responsible for everything relating to purchase and download, and until the app is installed on your device, you're in their hands.

Having said that, we're happy to offer what advice we can:

Google PlayTM
Other App Stores

If you're having problems purchasing or downloading from any other retailer, then that's who you need to contact in trying to resolve those problems. Links to the major stores selling TerraTime can be found on our Download page.

I had TerraTime on my old phone - how do I load it onto my new one?

Go to the app store that you bought the app from originally. Sign in with the same user ID that you used for the original purchase and you should be able to re-download the app without paying for it again. If this doesn't work, you'll need to contact the particular market in question for support.

I purchased the app with a different store account than I'm using now. Can I transfer it?

Unfortunately, none of the app stores provide a way for us to transfer app purchases from one account to another.

If you purchased it through Google Play, the best way to handle this is for you to purchase the app again, send us both the original and new order numbers, and we will then refund the original order – leaving the new order linked to your new account. It sounds like a hassle, but it does work out best in the long run.

If you purchased the app elsewhere (Amazon, Samsung, etc.), then I'm afraid we have even less control over purchases and accounts. Your best bet is to contact customer service for the store in question and ask them to transfer it for you.

Map and Globe

Why don't the clouds on my map/globe ever change?

Most likely, the app is set to Work offline; you can find this option in the first page of TerraTime's Settings screen.

Because the cloud layer updates every few hours, downloading this imagery can take a significant amount of bandwidth. And we've found that most TerraTime users don't much care about up-to-date cloud imagery – they're using other aspects of the app, or they simply want a realistic-looking map and globe. So to save on data charges all around, TerraTime defaults to working offline.

However, if you do want the near-real-time display, simply turn this option off.

The map and globe have odd, geometric shapes visible. What's the problem?

This is caused by occasional gaps or glitches in the satellite cloud imagery we use. They tend to be quite occasional, but there's not much we can do about them directly - we obviously don't have our own satellites!

The easiest fix is to simply wait a few hours; the satellite imagery updates automatically several times a day, so the problem should go away on its own. An alternate workaround is to disable the cloud layer until the problem sorts itself out.

What satellite data are you using?


The TerraTime globe looks shaky and moves around randomly. How can I stop this?

This happens as a result of issues with the hardware compass built into your phone or tablet. There are several things you can do about it:

Can you increase the resolution of the map/globe?

The imagery the app currently uses is already pushing the limits of available resources on many devices, and it already does a lot of adaptive scaling based on exactly what resources are available, including downscaling if resources run short. There may be some ways to improve this by using a different approach to generate the imagery, but that'll mean a complete rearchitecture of the graphics handling, and may come with other tradeoffs.

How do I install the live wallpaper?

Long-press in an empty area on your home screen, select Wallpaper, then Live Wallpaper, and either TerraTime Globe or Map. Change settings if you wish, then touch Set Wallpaper.

Alternatively (or if tht doesn't work), open Settings from the main TerraTime navigation menu, then select either Globe or Map, and check the box for Live wallpaper.

Will a solar eclipse show on the globe or map?

We're afraid not. Although the sun and moon often appear to "overlap" on the map around new moon, that's just because of the size of the icons - it doesn't mean that there's actually an eclipse. We are considering a companion app devoted to eclipses at some point, but it's quite a bit of work to do it right, and we haven't had time yet.

Does TerraTime show worldwide grayline projection on a full global map?

It shows an approximation of the grayline as the terminator on the map and globe. For a more detailed projection, you'll need a dedicated ham-radio app.

Why does the map/globe take so long to draw?

Downloading the various map images takes some time, even on a fast connection: these are big satellite photos. And creating an accurate day/night line involves a lot of calculations, especially given it's running on a phone.

In particular, it can take a minute to refresh the wallpaper when your phone is first turned on, due to all the other things that are happening during boot-up. Patience, Grasshopper!

Clock and Location

What does the blue-black boundary indicate on the clock, and what does the relative amount of blue and black on the clock face represent?

In short, the colors show day and night. On the clock, hours that are in the sky-blue area are daylight hours, those in the black area are night-time hours. So that also means that the color the hour hand is pointing to indicates whether it's day or night right now in the location the clock is set for.

The concept (and execution) are explained in more detail on the Clock page.

The 12-hour clock background abruptly switches from night to day at midnight. Can you please explain?

During the afternoon and evening hours, the entire 12-hour clock face is showing PM. So the 1:00 position is 1PM - daytime - and the 11:00 position is 11PM - nighttime. The 12:00 position is showing both noon and midnight (depending on which direction you're looking at it from), so it needs to be showing both day & night. At midnight, when the hour hand actually passes the 12, the clock face will switch from PM to AM and the day/night areas will essentially reverse.

This is actually how all 12-hour clocks work; the day/night visualization just makes the noon/midnight discontinuity more obvious. But it's not incorrect.

TerraTime does not show the right time for my location. How can I correct it?

First, be sure that it's actually wrong… TerraTime uses a 24-hour clock by default. This means that the position of the hour hand is different than on the conventional 12-hour clocks most of us are used to. You need to look at what number the hour hand is pointing to, rather than using your intuition of where it is on the clock face. [You can set the clock back to a 12-hour display in TerraTime's Settings, if you like.]

If the time shown genuinely is wrong, the most likely reason is that TerraTime has your location and/or time zone incorrect. Check these by tapping the location display (in green) at the top of the Clock or Compass page:

If all of that is correct, then the only other possibility is your device's system time and zone. Check those by going into Settings from your device's Home screen; they're under the Date and Time category.

How are you using the term solar transit and lunar transit?

As we use it, the term transit is essentially equivalent to zenith. We use it as outlined in the second definition here.

Why doesn't day + night = 24 hours?

Length of day is sunrise to sunset. Night is dusk to dawn. And between day and night is twilight, the period between dawn and sunrise, or sunset and dusk. So, day + night + twilight = 24 hours (with a bit of margin for roundoff errors and the change from one day and the next).

What do dawn and dusk mean?

Put simply, these two times are the end and beginning (respectively) of full darkness. However, there are a number of ways to define "darkness"; by default, TerraTime uses nautical twilight, the time when the sun is 12 degrees below horizontal. You can change this to civil (-6°) or astronimical twilight (-18°) under Settings > Clock settings > Dawn and dusk;

Why does TerraTime show a different sunrise and sunset time than _______?

You may see slight differences between the sunrise/set times shown here and in other places, including what you might observe yourself. There are several reasons why this happens:

Finally, it's simply not possible to compute rise and set times with a high degree of accuracy, due to unpredictable variations in local conditions like horizon irregularities and atmospheric refraction. See the US Naval Observatory's page on the subject for a good discussion of the issues.


My clock widget often stops on the screen. Once it's stopped I have to re-add it. What's the problem?

The only thing that we're aware of that will consistently cause the clock widget to stop is a having a task manager/"task killer" app running. If you have one of these, you'll need to add TerraTime to their "exclude" list.

Also, you probably don't need to re-add the widget if it stops. If you open the main TerraTime app (tapping on the widget will usually do this), you can restart any "stuck" widgets by pressing Menu > Refresh.

Why do you still have both resizable and non-resizable widgets on my Android 4 device?

The reason stems from Samsung, who didn't build their ICS TouchWiz home screen from the official Android 4 source; as a result, only Samsung's own widgets are resizable; third-party widgets (like ours) aren't.

Since Samsung is the largest phone manufacturer in the world, we couldn't just ignore this issue, so we've kept the non-resizable widgets around for the benefit of their users. Unfortunately, this means that it clutters up the list with unneeded widgets for the rest of us. Our apologies!

I'm trying to put a widget on my home screen but can't see any of your widgets on the list. What shall I do?

The first thing to check is whether the system has installed TerraTime to external storage (such as an SD card), which disables widgets. Open your device's system Settings, go to Apps, find TerraTime, and look in the Storage section. If it shows the app as being on the SD card, there should be a button for Move to internal storage. Tap this, and after it's moved, the widgets should be available.

The other possibility is an incomplete installation, which does happen occasionally. Uninstall the app, reinstall it, and hopefully the widgets should appear.


Do I need to be online for TerraTime to work?

Not usually. TerraTime's map and globe are created on the fly from high-resolution NASA images, downloaded as needed. So, a high-speed data connection is required to fetch these images the first time, and is required for live updates to clouds every few hours. Otherwise, the imagery is stored on your device after download, and no connection is needed.

Note that TerraTime Free, and the clock (in both editions), don't require an internet connection at all.

How much phone memory does TerraTime need?

The application itself takes about 20MB. Be aware that bcause TerraTime includes live wallpapers and homescreen widgets, it's not compatible with installation directly to SD card.

The images used to make TerraTime work are stored on your device after downloading; this speeds up the various displays, and allows the map and globe to be updated even when you're offline. If you have a memory (SD) card installed, these images will be stored there, rather than using scarce internal memory. You can decrease this storage requirement somewhat by turning off Clouds, Polar Sea Ice, and City Lights, if you wish.

What about battery usage?

Unavoidably, the TerraTime widgets and live wallpapers use somewhat more battery power than lesser-featured clock widgets and static wallpapers. If battery life is a problem for you, the impact can be reduced by increasing the Update interval, accessed in Settings from the main application menu.

What are the permissions that TerraTime is asking for and why?

Here's a list of the permissions that TerraTime requests, along with a brief description of each. Click on any of them for a detailed explanation.

sunrise and sunset times depend on where you are
to download the satellite imagery used to make the map and globe
to ensure that you have a high-speed data connection before downloads take place
to store various images for faster operation
essential to making the live wallpaper work

Does TerraTime do tides?

No, it doesn't. Although tides are intrinsically linked to the moon's (and sun's) gravitational pull, accurate tide times involve much more, being greatly influenced by the configuration of local waterways. As such, adding tides to TerraTime would greatly increase the size and complexity of the app; for example, just including the tide tables would make the app several megabytes larger. We believe that smartphone apps should be specialists, that they should "do one thing and do it well."

In that vein, there are some fairly reasonable tide apps already available for Android; we recommend TideApp and Tide Predictor.

Can I move TerraTime to an SD card?

Unfortunately, no. The app uses several features (like widgets and live wallpapers) that are incompatible with installation to SD card; this is a limitation of the Android OS. And even if you aren't using these features, we can't enable installation to SD without breaking the app for those people who do use them.

What's the difference between TerraTime and your other app, PolyClock?

TerraTime is about the natural flow of time as the Earth moves through space, while PolyClock is geared toward the human construct of time zones. The two concepts are obviously related, but they're different enough that we felt two separate apps could do them better justice than a single, all-encompassing app could.