Time keeping specifications for the oval face YES watches.

PCB Layout
The mother board is a tightly packed design connecting the chip with the LCD, quartz oscillator, transistors, EL light, alarm and other functions.

Following is a summary of the time data offered :

  • Hours, minutes and seconds in AM/PM or 2400 format.
  • 24-hour analog hand.
  • Noon on top, midnight on bottom.
  • Month, date and day.
  • Year, day of year and week number.
  • Times for sunrise, sunset and solar high noon.
  • Sunrise and sunset alarms 1/2 hour before and at event.
  • Equinox, solstice and cross-quarter alerts.
  • Moonrise, moonset and moon phase.
  • Percentage lunar illumination.
  • Time and date for next new and full moons.
  • Past / future date calculator for sun, moon and time data.
  • Time data capability for the years 2000-2099
  • Regular set alarm with 10-minute snooze.
  • 24-hour stopwatch with lap time.
  • 99-minute timer with alarm.
  • 9999-day count down / count up for set event time / date with alarm.
  • Programmed for 583 cities worldwide
  • Keeps digital time for 2 locations, HOME and AWAY.
  • 24-hour bezel can be used to keep time for a third time zone.
  • Location can also be set by latitude and longitude, time zone and one of 5 major DST systems.
  • Automatically adjusts for Daylight Saving Time worldwide.
  • DST can be set or adjusted manually.
  • Backlight for night time viewing.
  • Digital time can be turned off.
Oval Face Bezel

Based on complex astronomical algorithms using UTC time reference and whole degrees of latitude and longitude, the YES watch calculates sun, moon and time data once every 24 hours, at midnight HOME time.

We used algorithms published by the US Navy and Jean Meeus. An astronomer converted them into suitable language for programming.

Since every degree of longitude represents 4 minutes the sun and moon calculations carry an accuracy of +/-2 min. Since the moon waxes or wanes approximately 4% every day, 1% of illumination is about 6 hours.

Equinoxes, solstices and cross-quarter dates are subject to some cultural interpretations, so in our calculations we chose a mathematical mid-point between equinox and solstice.

Japanese digital quartz chip is specified to +/- 20 seconds a month.

Each sun and moon segment in the LCD display represents 15 minutes.

Each sliver in the moon phase display represent about 44 hours.

Procession of Equinoxes

The Platonic Year
The Precession of the Equinoxes.

There is a slight wobble in the earths axis, caused by an unequal gravitational pull of the sun and the moon. One wobble takes about 25826 years and consist of 12 zodiacal ages. During this period, the Earth's axiswill have pointed to each zodiac constellation in turn.This cosmic year is one of the longest cycles that are well-known to our astronomers.

Vernal Equinox
Time Specs