The Great Astronomical Cabinet Clock 2011-2014

Original, unique design. Precise, meticulous workmanship. Many years of patient, consistent, titanic work. A perfect combination of timeless classics and modern solutions, surprising with its possibilities.



8 years of work

The creation of the Great Astronomical Cabinet Clock took 8 years, including the assembly which took 3 years in itself. The project was finally completed in 2014.

Absolutely unique
through time.

The Great Astronomical Cabinet Clock 2011-2014 is a demonstration of the perfect synergy between tradition and modernity.

It is a coherent, precise and effective combination of precision mechanisms. This unique, original design, is a luxurious form.

Life goes on, time passes and even flies by, with so many different stories happening in just one second. This astronomical clock allows you to discover the total multidimensionality of time.



The clock has the following functions/indications:
1. second hand
2. hour dial – 12 hours
3. hour dial – 24 hours
4. date indicator
5. days of the week
6 months
7. years
8. ordinary/leap years
9. declination of the sun
10. sunrise
11. sunset
12. phases of the moon
13. time zones
14. planetarium
15. equal hours
16. unequal hours
17. Italian hours
18. Nuremberg hours



of operation.


Basic mechanisms and parts

  • drive –
  • Transmission
  • main mechanism – calendar
  • annual divider mechanism – planetarium
  • clock case (base, display case)
  • Mechanism
    time zones
  • Mechanism
    "Italian hours"
  • "Nuremberg hours"
  • Mechanism
    "equal hours"
  • Mechanism
    "unequal hours"
  • Mechanism
    of the tensioning



Drive mechanism (regulator)

The clock drive (regulator) drives the seconds hand axis and the minute hand axis of the main mechanism. The main mechanism controls the movement of the hands visible on the main dial, and the movement of the numerals visible in the four fields of the main dial – the year indication. It does not directly control the "sunrise", "sunset" or "sun declination” indications.

The main mechanism acts as a perpetual calendar. Depending on whether the year is ordinary or a leap year, it adjusts the number of days in a given month. No date adjustment is required. The main mechanism drives the planetarium's annual gearbox at a speed of 1 revolution/24 hours via the transmission mechanism. The annual gear axis makes a full rotation in 365 days.

Via a power transmission mechanism and a calendar device, it drives the 'sunrise', 'sunset' and 'sun declination' indications on the main dial. The minute axis controls the two time zone mechanisms via a system of sprockets and Gall chains. At a rate of 1 revolution/24 hours, the main mechanism drives four historic, single-indicator mechanisms that show the way time was measured in the early days of the mechanical clocks. These are equal hours, unequal hours, Italian hours and Nuremberg hours.

In order to maintain the correct indications associated with the annual gearing, such as planetarium, seasons, zodiac signs, sunrise, sunset and sun declination, the clock should be in constant use. Short interruptions in the normal running of the clock can be compensated for by rotating the minute hand until the current settings are reached. Longer intervals require the mechanism to be overdriven, avoiding the need to adjust the minute hand. The movement of the hands must only be clockwise, reversing the hands of the clock can damage the mechanism.

Drive mechanism

The regulator is a modern design the size of a small tower clock. Ball bearings have been used for all axes of the mechanism due to the need to increase the durability of the mechanism and reduce rolling resistance. The pendulum and anchor have been fitted with two knife supports resting on the prism sockets of the mechanism. The anchor-pendulum connection is equipped with a pendulum swing regulator and a safety device to protect the capture wheel and the pallets from damage in the event of a pulse failure. The seconds pendulum has thermal compensation. The mechanism has a cable tension. There is a reserve of about 50 hours of operation.




Transmission system

The transmission system distributes the drive in multiple directions and planes via sprockets, Gall chains, and drive axles.


The main component of the transmission system is the motherboard. It is located between the regulator and the main mechanism. Through a system of sprocket axes embedded in bearing bodies, it drives the individual clock mechanisms. In order to guarantee correct kinematic connections, each drive is equipped with longitudinal compensation, transverse compensation, adjustment – elimination of play through the use of weights, Cardan joints, and other safeguards necessary for correct operation.

Main mechanism



The main mechanism of Krzysztof Płonka's astronomical cabinet clock is a highly complex calendar device that controls all the clock's functions. The central axis of the main mechanism makes 1 revolution per hour – this is the minute axis. The minute axis drives the hour hand axis by means of gears. Through a system of gears, the drive of date, days of the week, phases of the moon, GMT (24-hour) indications, annual planetarium gearing, and a globe have been obtained.

At the top of the main mechanism is the second hand axis which has been integrated with the date axis. The date change is implemented using a cam, an impulse lever and a 31-tooth wheel.


Changing the date to the first day of the month automatically changes the rest of the clock settings. The mechanism has a complex date correction system depending on the name of the month and whether the year is an ordinary or a leap year. The automatic date change is carried out using cams, levers and a four-year correction for the number of days in the month of February.


The 24-hour dial, integrated with the moon phase mechanism, is visible at the bottom of the mechanism. The indication of the moon phases is carried out by means of a cam, an impulse lever, and a 59-tooth wheel.


A dial with the names of the days of the week is located on the left side of the main mechanism. Changing the settings is carried out using a cam, an impulse lever, and a 7-tooth wheel.


The indications of the year are located in the four fields of the main dial. The year indication mechanism consists of four rotating drums with digits from 0-9. The mechanism automatically changes the year when the month name is changed to January. The mechanical counter automatically changes readings over a period of 99 years. After this period, manual adjustments must be made in the fields located on the left-hand side of the main dial. Any change to the year causes the hands on the "ordinary years, leap year" dial to change. Located to the left of the date dial, it indicates whether the current year is an ordinary or a leap year. The mechanism controls the hand axis using cams, levers, an impulse lever, and a wheel with 8 teeth.


The main mechanism drives an annual gear – the planetarium – which makes one revolution in 365 days. Via the transmission system, the annual gearbox controls the 'sunrise', 'sunset' and 'sun declination' indications on the main dial. Indications are carried out by means of gear transmissions, levers, and control cams. The "sunrise" and "sunset" dials indicate at what time, the sun rises and sets, depending on the season. The "sun declination" dial indicates what the daily proportion of daylight hours and night hours is.


A planetarium is located in the central part of the clock case. The annual gear mechanism is driven by the main mechanism via the transmission system. The gearbox consists of a worm and a worm wheel with 365 teeth.

The entire system makes one revolution in 365 days.


A complex planetarium mechanism controls the rotation of the Earth and the moon's orbit around the Earth as it revolves. Additional mechanisms keep the Chronos figure in a fixed position relative to the front of the clock, and the moon ball in a fixed position relative to the sun so that the shadow on the side opposite the sun can be seen.


The position of the planetary system indicates the current season and the sign of the zodiac on two rings located around the planetary gear axis.


The time zone indications are located on two sides of the clock. They cover 24 time zones and 4 local time zones in the GMT system (3 hands each). The two mechanism plates contain hundreds of gears driving the minute, hour and 24-hour hands.


The time zone mechanism is driven by the minute axis of the main mechanism. Through a transmission system, i.e. a system of drive shafts, Cardan joints, sprockets, chains and weights for gravitational elimination of play, the minute drive reaches both sides of the clock where it is attached to the axes driving the mechanism. The time zone mechanism is synchronised with the indications on the main dial and does not require correction.


Equal hours, unequal hours, Italian hours and Nuremberg hours have been used to measure time since the Middle Ages. Since the first mechanical clocks organised life on earth to a significant extent, in homage to the first makers of mechanical clocks, Krzysztof Płonka's astronomical cabinet clock has been equipped with the above-mentioned mechanisms.


The 'equal hours' system, which replaced the extremely complicated 'unequal hours' system, has significantly simplified the reading of time.

In Krzysztof Płonka's astronomical clock, the main mechanism drives a single hand at a speed of 1 revolution/24 hours via transmission mechanisms. The clock face of the mechanism is divided into 24 hours.


The 'Italian' clock had a 24-hour dial, where the start of a new day, or the beginning of one o'clock, was the onset of dusk. It was then that the church bells announced the end of the working day. As the moment of sunset varies according to the season, the clock mechanism, with the help of gears and a cam, controls the clock face, which turns left or right depending on the season. The control cam makes 1 revolution/365 days. The single hand is driven by the clock's main mechanism via a transmission system at a speed of 1 revolution/24 hours.


The timekeeping system – known as 'unequal hours' – had a dial divided into 12 numerical hours from sunrise to sunset and 12 hours at night. Depending on the season, the hours were longer or shorter. Thus, in summer, daylight hours were longer and night hours shorter – and vice versa in winter.

Varying the length of the hours on sundials was not a problem, whereas obtaining such indications on the face of a mechanical clock was virtually impossible.

The 'unequal hours' mechanism in Krzysztof Płonka's clock largely allows for a direct reading of the current time without the need to recalculate corrections associated with the current season.

The 'unequal hours' mechanism has a dial divided into 24 parts, i.e. 12 day hours and 12 night hours. The dial face, by means of a control cam, makes an upward or downward movement in relation to the axis of the hand. The cam makes 1 revolution/365 days.

By moving the dial face, a reading of the current time can be made with a single hand. The hand receives an impulse from the main mechanism via the transmission mechanisms at a rate of 1 revolution/24 hours.


The 'Nuremberg hours' timekeeping system resembles the 'unequal hours' system in some respects – daytime and night-time hours also occur in this system. The main difference is that the length of the hours is equal, with the number of hours varying according to the season. In this system, daylight hours began at sunrise and night hours at sunset. The varying number of night and day hours depending on the season required the laying of special tables to regulate the clock.

The 'Nuremberg hours' mechanism, designed by Krzysztof Płonka and fitted to the astronomical clock by means of a high-complexity gearing, control levers and a control cam, makes it possible to read the current time directly, as well as the number of day and night hours. The dial of the mechanism consists of two mechanical systems on which the hours are marked from 1-16. The cam-controlled dials shade each other depending on the season, allowing the number of night and day hours to change. A single hand indicates the current time. The control cam is driven at 1 revolution/365 days, while the hand is driven at 1 revolution/24 hours.

Thanks to this innovative system not used in the original mechanisms, it is possible to read the hours directly without having to adjust the clock or use plates.


In order to wind up the clock, a crank is applied to the quadrant of the winding axis. The axis of the tensioning mechanism is attached to the wooden clock case by two brackets fitted with ball bearings to reduce rolling resistance. A sprocket mounted on the tension axle via a Gall chain and a second sprocket integrated into the drum axle of the clock drive mechanism's cable weight allows it to be tensioned.

Clock housing

The clock housing consists of a base, two side segments and the main mechanism case. It has been handmade from mahogany wood and polished.


Clock housing



The clock is equipped with a box containing a set of tools that may be needed during operation. The equipment includes a crank for winding the clock, special keys for setting the hands, a universal puller for pulling off the hands and Allen keys.

The tools are housed in a designed and handcrafted box finished in mahogany wood.



Rules for using the clock

Due to its size and weight, the clock must be partially disassembled for transport and then reassembled once in position. The room where the clock is located should be dry and at the right temperature. The clock must not be exposed to shocks. Comprehensive information on the construction and rules of use is provided by the clock maker.

Basic operating principles:


The clock is to be wound up using the crank provided. Systematically check the condition of the weight cable.


Only adjust the display using the keys provided.


Do not reverse the hands of the clock – you risk damaging the mechanism.


If the clock is disturbed, under no circumstances should the mechanism be tampered with. Any faults can only be rectified by a professional.


Periodically – every 4 to 5 years – the clock mechanisms should be maintained and lubricated.

Observing these rules ensures the correct operation of the clock for many years.

  • Technical data: height – 290cm, width – 110cm, depth – 105cm, weight – approx. 450kg

Krzysztof Płonka

Krzysztof Płonka

He was born in 1952 in Ślemień near Żywiec, where he lived and attended primary school. In 1966, he began studying mechanical engineering, machining and precision mechanics in Bielsko-Biała. He has been self-employed since 1990. Since the beginning of his career, clock constructions have become his lifelong passion.

It deepens the knowledge of the history and construction of mechanical clocks, and at the same time rebuilds unique, antique clocks, restoring them to all functions, which allows them to operate.

In 2005, he obtained a patent for the "Chronometer Clock Grab" No. 204808, which he designed.

During this time, he begins building astronomical clocks of very high complication and "Regulator" type standing clocks.

Currently, he is working on the implementation of Krzysztof Płonka's "Great Astronomical, Figural Tower Clock" and rescues old, antique mechanical clocks from total oblivion by restoring their utility functions.


Autorski, unikatowy projekt. Precyzyjne, drobiazgowe wykonanie. Wieloletnia, cierpliwa, konsekwentna, tytaniczna praca. Perfekcyjne połączenie ponadczasowej klasyki z nowoczesnymi rozwiązaniami, zaskakujące możliwościami.

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