Astro Clock with Sun moving in the Ecliptic
(Showing date and 30 degree Zodiac signs)

 This clock shows the constant changing position of the ecliptic (Zodiac) above the horizon
The Sun stays in the ecliptic at a high position in the sky in summer and a lower one in wintertime

(the difference in time at my location is in summer 1h 40m and in winter 40m, the hands on the photo were not yet adjusted) 




Sunset 4 june 2011 at 21h 53m  (Equation of Time -1 min 41 sec)




Only at his highest point in the ecliptic - round midsummer - the Sun stays visible all night



The clock mechanism just after polishing and waxing




 Side view of the clock



The wheels for the sky plate



First test with the Sky plate
(This sky plate moves in 23h 56m 3.93s, the sun in 24h)



Experiment with a groove as ecliptic
(the quarts clock was not strong enough, every attempt failed)



Several types of hands were tried
(but they all where to heavy and did not work)



The solution was to use a circle with ecliptic line, rotating around a disk
( the centre plate with the stars)



Some parts of the clock



The support for the Skyplate



The back side with quartz clock
(the text is in Frisian, in free translation 'a small mistake is human')



Trial and error
(There is always some play in the wheels but the use of small weights gives a constant pressure and makes the clock more stable)



 The wheel for the weights


(Because the difference in the weights was about 50 grams the line was sliding too easy, after knurling the wheel the problem was solved)



Connecting the main axle to the quartz clock
(difficult to see but there is also a small pin in the hour tube of the quarts clock to prevent sliding)



Photo while polishing a wheel
(photo - Mieke Merckx)


To the main page