Emerald Chronometer

Emerald Chronometer® is an iPhone™ application that models high-end mechanical watches. These models contain many of the most complex "complications" found in real watches, plus refinements found nowhere else. All displays maintain the look and feel of real mechanical objects, but with the time and location accuracy of the iPhone.

This app was originally written by Bill Arnett & Steve Pucci of Emerald Sequoia LLC and was available on day one when the App Store opened in 2008. It has won numerous awards including “App Store Pick of the Week” in July 2008 and Apple “Staff Favorite” in December 2008. After updating and maintaining the Emerald Chronometer and their other apps for 14 years, Bill and Steve decided to shut down Emerald Sequoia.

Emerald Chronometer was transferred to Scapa Flow, LLC. I have put the Emerald Chronometer back on the App Store and will do my best to maintain it and update it with future iOS updates. I may add some new faces but am not sure of the timeline for this.

The original code can be found here on GitHub.

Steve created a browser based version of Emerald Chronometer HD which can be found here or downloaded from GitHub and run locally with no server required (see instructions here).

Clock Features:

  • Local, UTC time

  • Day/date/month/year indicators, using mechanical wheels

  • World-time watch with 24-city ring on one side and 4 subdials on the other

  • Chronograph (stopwatch) with split timer

  • Alarm clock and interval timer

  • Most watches with 1/5 sec or 1/10 sec precision

  • Synchronized with standard atomic clocks via NTP

Astronomy Features:

  • Highly accurate data from 4000 BCE to 2800 CE

  • Rise and set times for the Sun, the Moon and the 5 classical planets including a unique face showing the rise and set times of all 5 classical planets plus the Sun and the Moon at once

  • The correct shape and orientation of the Moon in all phases but still using a mechanical display

  • Relative positions of the Sun, Moon, 6 planets and the constellations of the zodiac

  • Times of the solstices, equinoxes and apsides; position of the Earth's terminator

  • Eclipse predictor (lunar node indicators and separation indicator)

  • Relative positions of the Sun, Moon and the constellations of the zodiac

  • "Compass functions" show the elevation and azimuth of the Sun, the Moon and 5 planets; twilight times

  • User settable geographic location and timezone using an 80,000 city database

  • The Equation of Time, solar time and sidereal time