Joined
·
98 Posts
I thought this might interest a few clock people. I picked it up at auction here in Brisbane a few months ago, quite a find, just finished getting it working again. It has a complicated moon feature and the curved slides in the top arch to the right and left I think give the daily sun rise and set times. The whole of the back blue area is the night sky on a big disc which does a daily rotation. Set within that disk is the smaller moon disk which also rotates independently, giving the daily changes in the moon phases. Below in the main dial can be seen a brass date hand as well as the hour and minute hands. The two smaller central dials are interesting too. The bottom one indicates the months and the top one indicates when the sun is "faster" and when it is "slower" and includes a load of odd numbers which I believe indicate the equation of time and described here from wikipedia " The equation of time was used historically to set clocks. Between the invention of accurate clocks in 1656 and the advent of commercial time distribution services around 1900, one of two common land-based ways to set clocks was by observing the passage of the sun across the local meridian at noon. The moment the sun passed overhead, the clock was set to noon, offset by the number of minutes given by the equation of time for that date. (The second method did not use the equation of time; instead, it used stellar observations to give sidereal time, in combination with the relation between sidereal time and solar time.) The equation of time values for each day of the year, compiled by astronomical observatories, were widely listed in almanacs and ephemerides" This has certainly had us all in the clock collecting fraternity here scratching our heads, any Astronomer types or otherwise out there care to comment
Thanks
Phil
Thanks
Phil
Attachments
-
617.1 KB Views: 1,100
-
134.7 KB Views: 956
-
126.1 KB Views: 886
-
275.9 KB Views: 907
-
110.2 KB Views: 904
-
99.2 KB Views: 904
-
96 KB Views: 885
-
171.3 KB Views: 933
-
204.9 KB Views: 1,056