Emerald Sequoia LLC
Emerald Chronometer for Wear OS
How to Buy

Emerald Sequoia LLC will be shutting down at the end of 2023. Please see our blog post here.

Thanks for all of your support over the past 15 years!

Emerald Chronometer Support
Wear OS products


I purchased your app, but my watch is still displaying the same face -- How do I see the faces on your app?
Use the main Wear OS watchface chooser to select a face (all of our face names start with "Emerald "). To access the chooser, press down and drag left or right when viewing a watch face. All the way to the right of the favorites row is an "Add more watch faces" button -- tap that to access the list of installed faces that have not yet been selected in the favorites row.

The only face I see starting with "Emerald " is "Emerald DEMO". Where are all of the other faces you describe here?
If you download Emerald Chronometer (the free app), this is the only face that is initially available (Emerald Chronometer Pro, the paid app, includes all faces immediately when you buy it).

If you select "Emerald DEMO", it will run through a demonstration of all of the other faces. At any time, you can tap on the running demo to bring up buttons to pause, go back, go forward, or bring up the info panel.

From the info panel you can tap a button to buy (all 21 faces). The faces you purchase in this way will then be visible in the main face chooser alongside Emerald DEMO.

The sunrise/sunset times are wrong.
The first thing to check is whether your device has the correct location, time, and time zone. An easy way to check whether your watch is set up properly is to visit the device info panel. There you should verify three things: If the location listed isn't correct, there are several possibilities: If the timezone on the device info panel isn't correct, you can go to your (watch) device's settings, and check the timezone setting. In most cases it should work to automatically set the timezone from the network, but if this isn't working, you can disable that option and set it manually.

If the time isn't correct, check the settings on your watch device (Settings -> System -> Date & time -> Automatic Date & time).

Will Emerald Chronometer work without an Internet connection (eg. out in the wilderness where even cell phone service is unavailable)?
Yes, so long as the device has a way to get the accurate location. Time and location are all that we need; all of the astronomy calculations are done internally with no Internet required. In such situations you can put your device in Airplane Mode once it has gotten the right location (you can check the device info panel to verify the location).

Is there a version for the Apple Watch?
No. Apple does not allow developers to create custom watch faces.

These faces are expensive! And for such a small device!
Emerald Chronometer for Wear OS is the product of literally years of part-time work by the developers designing, implementing, documenting, and testing (we're a two-person company and we do it all in-house). Even the "port" from our iOS phone product took over a year, as it required adapting to a new form factor and OS, and more importantly re-implementing the majority of code which was written in Objective-C.

We don't expect to recoup the value of all that effort with our sales on Wear OS, but we do believe it's a fair price for what you get:

Fans of real mechanical watches know that the size of the object doesn't correlate with how expensive it is. :-)

I'm seeing crashes (Emerald Chronometer just abruptly disappears or hangs).
This should be rare, but if it happens, here are some things to try, in order of increasing effort:
Mauna Kea shows the Sun in Cancer on Aug 3 but Cancer is June 23 – July 22.
It's because of the precession of the equinoxes and the inaccuracy of the calendar prior to the Gregorian Reform of 1582. Mauna Kea's zodiac dial shows the present astronomical positions of the constellations which have changed considerably from their positions when the astrological dates were fixed in ancient times.

But Mauna Kea doesn't seem to quite match the astronomical constellations, either.
Right. MK divides the zodiac into twelve equal sections and labels each one with a constellation. The actual constellations are not all the same size, so MK's labels are only approximate. The numbers in between each constellation label, however, do accurately indicate right ascension (measured in hours). Basel shows the actual constellation boundaries (for the present epoch).

Your definition of "complications" is different than the one used in Wear OS (and Apple Watch, for that matter).
The use of the word "complication" in the context of a watch predates smart watches by a century or two. :-)     It's a term of art in the horology (fancy watch) world, and refers to any watch display other than hours, minutes, and seconds (and sometimes simple day/date). See:
The collection of faces contained in Emerald Chronometer has a very large number of complications; here's a list.

The times for moonrise and moonset are not consistent between the various faces.
Emerald Chronometer uses different rules for the "ring"-type displays like Mauna Kea and for the "dial"-type displays like Haleakala:

The "dial"-type displays use rise and set times for the current day (i.e. the day shown in the date windows), except in cases when the event doesn't happen on that day in which case it just displays 00:00 (this happens a couple times a month for the Moon and in summer and winter at high latitudes for the Sun). The values are updated at midnight.

On the "ring"-type displays, we use a more complicated algorithm but the result is simpler. The rings show the closest rise and set time to the current time without regard to the day or whether that's before or after the current time. (In detail: if the Sun is above the horizon then the sunrise indicator shows the time of the previous sunrise and the sunset indicator shows the next sunset; but if it's nighttime then the sunset indicator is shows the time of the last sunset and the sunrise indicator shows the time of the upcoming sunrise. The sunrise time is updated at sunset and vice versa. Similarly for the Moon.)

Since the times of sunrise and sunset change by only a few minutes per day the differences between the two rules are small. But the times of moonrise and moonset change by about an hour each day so the differences are readily apparent.

Mauna KeaRingnext/prev
Mauna LoaRingnext/prev
HaleakalaDialfor day
HanaDialfor day
GenevaDialfor day
VeneziaDialfor day

OK, but Padua seems to be different from either the Ring or Dial rules.
Right. Because Padua only has a single horizon indicator for all of the planets (we use "planet" to refer to the Sun and Moon too, in this context), it is only a rough indication for any particular planet and can be wrong in certain situations; use Venezia if you want precise information. Specifically, the horizon indicator shows only the azimuth of the intersections of the ecliptic plane with the horizon, and thus is only exact when read against the Sun hand (or against another planet's hand if the planet happens to lie exactly in the plane of the ecliptic). If the planet is outside the ecliptic plane (that is, if its ecliptic latitude is nonzero), then the horizon indicator for that planet can be wrong in two circumstances:
  * Close to the time of rise or set
  * Close to the time when the ecliptic plane passes through the zenith, as it does in tropical latitudes.
So the bottom line is that the horizon mask should be taken as a rough guide only. Use Venezia if you want more precise info.

When Haleakalā (and Venezia) show the exact time of sunrise, the altitude hand for the Sun is a little below zero (and the same for moonrise and the altitude of the Moon).
Yes, that's right. Sunrise is defined to be the time at which the first bit of the Sun's disk is visible. But the Sun's altitude is defined as the altitude of the center of the disk. It takes several minutes for the Sun to move that far.

I have a real watch that displays the Equation of Time. It shows a value that's not the same as yours.
We adopt the convention that a positive number means the sundial will show a later time than an ordinary clock. IE:
      EOT = sundial time - standard time
Some watches use the opposite convention. Learn more about the Equation of time here:

My eyes aren't what they used to be and some of those dials and hands are awfully small. Can you implement a zoom feature?
Wear OS actually has a nice built-in zoom feature. Go to Settings -> Accessibility and turn on "Magification Gestures". This will allow you to triple-tap to zoom into an area of the watch. And if you hold the final tap ("tap tap hold") you can then drag your finger around the face to see the various features.

Why is it asking to use my location?
Emerald Chronometer needs to know your location in order to compute various astronomical quantities (eg. sunrise time). That's all we use it for. The data is stored on your device only. We do not transmit it anywhere. We do not sell it to anyone. We update it about every thirty minutes (sometimes more often if something else on the device is also using the location).

Since I bought Emerald Chronometer, I've started getting spam about watches!
Emerald Sequoia has not ever sold, nor will we ever sell, email addresses of our customers or of anyone else who contacts us via email. We hate spam as much as you do.

It sure would be nice if ...
Don't hesitate to send us enhancement requests or ideas for new faces. Some of the ideas we've gotten have been really interesting! We're only a two-person company doing this part-time, so we can't promise if or when any particular request will be implemented.


We work hard to make Emerald Chronometer as close to perfect as we can. But we're realists. And we're here to help. So if you have a problem just send mail to
Please read the documentation and check the FAQs first. Make sure you have the latest version (see the Release Notes); it's displayed in the device info panel. We try to respond quickly (usually within a day or two) but we're only a two-person company so occasional delays are inevitable.


We would also very much appreciate any comments you may have about how we can improve Emerald Chronometer in the future.

Release Notes

Click here to see what's changed in each release.

Copyright © 2018, Emerald Sequoia LLC; last updated: 2015 Mar 1

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