Post by GLADIATOR on Jan 23, 2013 11:02:25 GMT -6
What is considered 'the' most difficult complication on a watch?
Repeater, Equation of Time or Perpetual Calendar? Probably Perpetual Calendar?
Now:
Equation of Time. Difference between clock time and 'sun' time. We divide day into 24 equal hours, true solar time may differ.
Now the earth has an elliptical shape and the earth's axis is also tilted, therefore, the the length of the true sun day varies i.e, NOT 24 hrs!.
Between the longest and shortest sun days there is a difference of 30 minutes and 45 seconds, between the longest day in the summer to the shortest day in the winter.
Remember OUR watch is just ALWAYS 24hrs!!
So to make a watch that shows both 'clock time' and 'sun time'. To do this, they either have two minute hands or two seperate pair of hands.
BUT the HEART of such clocks is a kidney shaped disc that turns on its axis ONCE a YEAR!!
How amazing is that?
Perpetual Calendar. Programmed to 2100.
Note: 2100, 2200 , 2300 Need DROP extra day. There after Leap year days must be dropped every 4000 yrs.
@ 45 BC Julius Caesar developed the First Calendar (June is named after him), to try to compensate for above he added a leap year EVERY 4 yrs. Big mistake! By 1500 We were some 15 days behind!!
So in 1582 Pope Gregory X111 developed the Gregorian Calendar. Which adds 1 day every 300 yrs
However even that would NOT be accurate, so in 2100,2200, and 2300, we MUST drop that EXTRA leap year day
There after Leap Year days must be dropped every 4000 yrs!
Now a Perpetual Calendar watch does NOT just calculate 28, 30 or 31 days/month. But EVERY leap year to 2100 (Remember 2100 will NOT be a Leap Year)
To do above mechanically is an amazing feat. A wheel that turns one every 4 YRS!!!!
How Amazing is that!!
Regards
adam
Repeater, Equation of Time or Perpetual Calendar? Probably Perpetual Calendar?
Now:
Equation of Time. Difference between clock time and 'sun' time. We divide day into 24 equal hours, true solar time may differ.
Now the earth has an elliptical shape and the earth's axis is also tilted, therefore, the the length of the true sun day varies i.e, NOT 24 hrs!.
Between the longest and shortest sun days there is a difference of 30 minutes and 45 seconds, between the longest day in the summer to the shortest day in the winter.
Remember OUR watch is just ALWAYS 24hrs!!
So to make a watch that shows both 'clock time' and 'sun time'. To do this, they either have two minute hands or two seperate pair of hands.
BUT the HEART of such clocks is a kidney shaped disc that turns on its axis ONCE a YEAR!!
How amazing is that?
Perpetual Calendar. Programmed to 2100.
Note: 2100, 2200 , 2300 Need DROP extra day. There after Leap year days must be dropped every 4000 yrs.
@ 45 BC Julius Caesar developed the First Calendar (June is named after him), to try to compensate for above he added a leap year EVERY 4 yrs. Big mistake! By 1500 We were some 15 days behind!!
So in 1582 Pope Gregory X111 developed the Gregorian Calendar. Which adds 1 day every 300 yrs
However even that would NOT be accurate, so in 2100,2200, and 2300, we MUST drop that EXTRA leap year day
There after Leap Year days must be dropped every 4000 yrs!
Now a Perpetual Calendar watch does NOT just calculate 28, 30 or 31 days/month. But EVERY leap year to 2100 (Remember 2100 will NOT be a Leap Year)
To do above mechanically is an amazing feat. A wheel that turns one every 4 YRS!!!!
How Amazing is that!!
Regards
adam
