Creating instruments to tell time has been connected to religion from the start. The first mechanical clocks for instance often had blank faces and were located on towers so that people would know when services would be. Despite the fact that today clocks and watches are part of everyday, secular life, combining the jigsaw pieces of calculating the dates of the Eastern Orthodox Easter with the regular workings of a clock movement is mesmerizing.

Konstantin Computus Easter is tied to the Russian Orthodox Calendar. This clock identifies the moving date of Eastern Orthodox Easter, a date that is calculated based on numerous rules and limitations. To fully appreciate the complexity of this movement, one needs to try and calculate the date of Easter oneself. The factors include: lunar cycles, solar cycles, the indict, the epact, the solar correction and more. Konstantin Chaykin learned how to use all of these factors created his own method for doing the computations and ‘taught’ his clock how to compute the dates for Eastern Orthodox Easter.

The case of The Computus Easter Clock is designed to look like the St. Isaac Cathedral of St. Petersburg, Konstantin’s home town. The Computus Clock is related to the 2007 Resurrection Clock, also a complicated astronomical clock. The Computus Clock has a more complicated movement for calculating the moveable dates of Easter and appears as a Great Russian Orthodox cathedral.

The movements and the appearance of the Computus Clock are equally complicated and beautiful. Anyone who has even seen photographs of St. Petersburg will recognize the references to the St. Isaac Cathedral in the overall shape, the dome, the colonnade, the lantern, the gables, the bell towers and the colors. The colors of the marble on the Computus Clock case match the colors used inside the Cathedral.

The dome of St. Isaac’s is a landmark in St. Petersburg: among the largest in the world, it’s gilded shape is visible from land and sea. The Computus clock is surmounted by a dome gilded in the guilloche technique and covered with gold enamel. Konstantin visualized the case as a symbol of Easter, thus the dome melds into an egg shape. The egg is an important symbol of the Resurrection for all Christians, who have been giving each other eggs on Easter since ancient times.

The lantern on the Computus Clock, just like the lantern on St. Isaac’s is the crowning element in the design. The lantern creates a feeling of airiness and unearthliness. The elegant contrast between the size of the dome and the size of the bell towers emphasizes the monumental shape of the dome. The four miniature bell towers on the Computus Clock gracefully frame the central dome. The colonnade of St. Isaac’s is a massive structure, which is a unique landmark in and of itself. The Computus Clock is also surrounded by 24 columns, which act as hour indicators for the function ‘Times of Russia’ – a system for identifying the time in all of Russia’s time zones.

The facades of St. Isaac’s are decorated with gables upheld by monumental granite columns embodying eternity. Once again, the Computus Clock includes these themes: eternity in the eternal calendar with the eternal cycle of Easter and visually in columns which frame the movement. There are less columns on the clock than on the Cathedral for the columns on the clock reveal glimpses of the secrets of time. The gables of the Cathedral resemble eagles with outspread wings. Four of the gables are decorated with energetic, yet massive bas-reliefs.

The Computus Clock includes details from the north gable – ‘The Resurrection’ and from the south gable ‘The Visit of the Magi’. Expert stoneworkers lovingly reproduced these details in mosaics. The case also includes some imagery and themes from the Cathedral’s interior: the designs on the roof mimic the floor of the Cathedral and the mosaics on the sides of the case are based on the stained glass window ‘The Risen Christ’ and the mosaic of Archangel Michael.

The indicator of Eastern Easter is located on the face of the Computus Clock. This indicator includes the date according to both the Julian and the Gregorian calendars. There is a separate row of dates for each calendar. The lower row is for the Gregorian calendar and includes dates from April 4 to May 8, while the top row is for the Julian calendar and ranges from March 22 through April 25. To make it easier to read the dates, they are color-coded by month. Instead of a hand, there is a square frame which contains the dates for the given year from both calendars. The dates change every year on New Year.

On the back of the movement there is a mechanism to balance the discrepancies between ‘real’ time and the 24 hour day; a discrepancy created by the imperfect shape of Earth’s orbit and the 23° angle of the Earth’s axis.

The mechanical heart of The Computus Clock, the proprietary movement which manages 16 time-telling functions, is the result of over 10,000 hours of hand labor. This heart beats at 18,000 vibrations per 30 minutes. The master clockmakers perfected each of the 1,275 miniscule parts of the clock. In addition to indicating Eastern Orthodox Easter, the Computus Clock has the following functions: phases of the Moon, the winding power left, the time equalizer, a star map, indication of the days of the week, the date, month and year by the Gregorian calendar, including leap years.

Today, The Computus Easter Clock is the most complicated clock ever created in Russia. Developing the plans alone took over 3, 000 hours. Creating and assembling the parts, regulating and adjusting the clock called for all of the skill, artistry and experience of Konstantin and his team at the Konstantin Chaykin Manufacture. And the result is awe-inspiring. The Computus Easter Clock is the pride of the Russian watchmaker and a wonder for the rest of the world.

Specifications
Movement
Manufactory caliber: Т03-0
Materials: brass, steel, bronze, anodized aluminum, gold, lapis lazuli and sapphires
Frequency: 18 000 vibrations per hour
Jewels: 16
Bearings: 68
Movement parts: 1375
Escapement: anchor
Power reserve: up to 10 days
Movement accuracy: ± 20 seconds per day

Case
Dimensions: 600*340*242 mm
Materials: marble, brass, silver, steel, duralumin, mineral glass, gold, flint, rhodonite, violan, xonotlite, lapis lazuli, charoite
Additional technology: guilloche, hot enamel on guilloche surface, mosaic

The minerals in the mosaics:
Gables: flint, rhodonite, violan, sandstone, xonotlite, lapis lazuli, charoite
Mosaic with the image of Archangel Michael: jasper, violan, sandstone, magnesite, jade
Mosaic with the image of “the Risen Christ”: jasper, marble, jade, lapis lazuli, violan
Top of the housing mosaic: marble, flint

Features:
One-minute tourbillon
Hour
Minute
Second
Date of Orthodox Easter
Moon phases
Power reserve
Equation of time
Star chart
Sidereal time
Russia time zones
Seasons

The functions of the perpetual calendar:
Day of week
Date
Month
Year
Leap year

Patents:
№ 2353978: “Calendar device and method for orthodox Easter date determination”
№ 2306618: “Calendar device for determining orthodox Easter date and orthodox holy days”
№149239 “Clock with display of time in time zones of Russia (options) and method of simultaneous display of time in all time zones of Russia”