#39611 - 03/26/08 03:01 AM
Re: Greenwich Longitude off by 106m in Keyhole?
  
[Re: LionelB]
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Traveler
Registered: 03/16/08
Posts: 2
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Quote:
You can cross the meridian on the park's <b>Boating Lake!</b> The Millennium Sundial by the lake is some <b>2 metres OFF</b> the Meridian due to incorrect information being supplied. The diallist is unhappy about this as it makes the sundial incorrect by about 8 minutes but it is difficult to see how it could be rectified.
2meters=> 2m/(40000000(m around earth)*cos(51.5))*86400(sec/day)= .007 sec off, not 8 min off. And .007 sec cannot be read on the dial of a sundial. Even Oxford is only 5 min off (see the definition of time at Christ Church College which still goes by sun time, and which differs by 5 min from everyone else's time). And the analemma means that the time is off by up to 15 min per day at different parts of the year anyway. While I would certainly have been upset had I been the dial maker, it would not because that 2 meters makes any difference to the accuracy of the sundial. (And since noon is determined by the 0 latitude, which has shifted, it is actually off by 104.5m,or .3 sec, not 2 m ).
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