Anyone with an interest in time and time keeping will want this must-have app for the iPad. It’s the new big brother to the awesomely beautiful Emerald Chronometer (EC) for the iPhone that was launched in July of 2008. One of the significant features is that it accesses NTP time standards, thereby assisting with the clock drift of the Wi-Fi iPad. While it may not replace the professional equipment that astronomers use, it will nevertheless delight amateur and professionals alike.

Take a quick read here before you decide it’s too complex or technical for you.

The Basics

This is a quick look review because there is so much variation and depth to this app, it would require an entire magazine to explore and document its depths. Basically, Emerald Chronometer HD (ECHD) expands the original iPhone version to the full iPad display with breathtaking results. There are 15 watch designs to chose from with 26 total watch faces.

Watch selection

Each watch has its own distinctive style and functions. For example, the “Mauna Kea” watch is focused on astronomical time, “Thebes” is a count-down timer and “Olympia” is a chronograph/stopwatch with 0.1 sec accuracy. The reference page for each watch can be printed. (I use Printopia.) For example, selecting “Haleakala,” a watch focused on astronomical rise and set times, brings up this display with sunrise, sunset, sun azimuth and elevation. (Note how it uses compass marks around the edge and the slim green and blue hands.)

Haleakala watch (front)

Touch the cycle button the bottom left, and the back of the watch displays moonrise, moonset times, moon azimuth and elevation. Most other watch types have complementary data on the back.

Haleakala watch (back)

The full list of features is available on the iTunes page, so I’ll just point out a few. The calendar data is accurate from 4,000 BCE to 2,800 CE, so you won’t have to worry about any limitations in your lifetime. NTP time sync is within 0.05 sec.

Touching the green dot on the upper left displays the app’s data related to NTP servers, accuracy, and how far off the iPad’s internal clock has drifted.* The developer told me: “EC and ECHD will try a number of different servers if it needs to, but if the first one is successful (by which we mean its error bound in either direction is less than 0.05 seconds) we won’t go further than the first host (though we also reject hosts whose reported internal errors are large). The NTP code in EC/ECHD is somewhat different from that in Emerald Time, though the former is derived from the latter.”

Time Info

Touching the green dot on the upper right displays your location data, derived from Apple’s Location Services API (which has changed methodology over time).

Location Info

Here’s a sample of the info page for just one of the 15 watches. It’s all you could ask for in a US$4.99 app.

Complete info for “Istanbul” watch theme

How Do They DO that?

I asked if these watch faces were generated on the fly. The answer is, well, partly. The developer explained: “The straps and case externals are Photoshop constructs. Almost all of the hands and dials (with the major exception of McAlester) are generated with graphics calls (lines and polygons), though not on the fly. For performance reasons, we use OpenGL (primarily in 2D mode) to draw all of the parts out of a parts list we use as an OpenGL texture atlas. The hands and dials are generated using a custom tool we wrote for this purpose, which generates the image for each part and lays out the atlas automatically.”

“Geneva” Atlas of objects

A Final Taste

I want to show you one more watch face to whet your appetite for this app. It’s the “Mauna Kea” face that has many of the elements of Emerald Observatory.

Mauna Kea face

It’s just astonishingly beautiful and represents some really fine work by these developers on the iPad.

How do EC and ECHD Differ?

• ECHD displays higher resolution images on the iPad rather than running in iPhone emulation mode
• ECHD has options pages that are optimized for the larger display (though with the same functionality).
• ECHD runs in both landscape and portrait; regular EC only works in portrait.

Summary and Recommendation

I haven’t begun to touch on all the features and all the watch types. This quick look review is intended to introduce you to the elements of the app, show you how it looks, explain some of the operation, and make a recommendation. I have been in contact with the developer for some time now, starting when I reviewed the drop-dead gorgeous Emerald Observatory and they know what they’re doing with time and astronomical calculations. Of course, that doesn’t guarantee that there isn’t a small glitch somewhere in this rather complex app, but I also surmise that the developers have the experience and smarts to fix any such problems.

Even if you aren’t into astronomy, this app is recommended for anyone who wants to explore time, use an iPad as a clock/count-down timer/stopwatch, showcase what the iPad and iOS SDK can achieve, or just have some fun. As mentioned above, if you have a Wi-Fi only iPad, you can find out how far the internal clock has drifted. If you’re an amateur astronomer, the combination of this app and, say, Sky Safari, will bring a lot of high technology to your observing session. Heck, even if you’re just trying to keep your (model or real) trains running on time, it’s a great app. The uses are many.

Because this app offers so much for the money, works flawlessly, keeps and displays time in so many useful ways and is awesomely handsome, it gets an “Outstanding” rating, 5/5.

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* References:

What Time is it? Your iPad May Not be Sure

What Time is it? Your iPad 2 *Still* Doesn’t Know