Astronomical Clock

This clock is still under construction. Photos will be added shortly showing the current state.

A view of the front showing the large balance wheel at the bottom and the 'complication' dials

The rear showing the balance impulse coil, the driving weight and rewind system and the rear of the Brocot perpetual calendar. Note the 4 year 'program wheel' that describes the days in each month

The clock has an electromagnetically impulsed large horizontal balance whose frequency is controlled by a rather large hair spring. The period is 4 seconds and is regulated by a motor operated 'finger' which pushes against the hairspring.

Apart from some steel screws and shafts the whole clock is constructed of wood.

The power for the going train and complications is supplied by a weight driven electrical rewinding system. The power train is regulated by a swiss lever type escapement which is latched and unlatched by the balance wheel. Thus the balance wheel is essentially free other than when it is operating the lever.

A more detailed view of the impulse coil and the four second balance wheel.

A view of the stepper motor controlled cam which moves the 'finger' which controls the movement of the 'hairspring' and thus regulates the balance.












The clock has 'complications'. As well as showing mean time it has a  display showing the  star field visible from 50 degrees North and with sidereal gearing this display rotates throughout the day and night.

The upper portion of the clock has a perpetual calendar modelled after a design by Brocot showing date, day, month, moon phase and the Equation of Time. The calendar is perpetual in that it accounts for 31, 30, and 28 day months. Also it can cope with leap year Februarys and so will be accurate up to the year 2100 when it will need manual updating.

It is hoped that the clock will be surmounted by an orrery showing the motion of the planets but the design of this is not finalised yet.

A view showing the escape wheel  of the lever escapement and the contrate wheel which turns the power drive through a right angle.

More photos to follow