[LEAPSECS] Time on time

Rob Seaman seaman at noao.edu
Wed Nov 30 14:08:39 EST 2011

On Nov 30, 2011, at 11:45 AM, Hal Murray wrote:

>> Speaking of time, what sort of time is the Long Now clock keeping, anyway?

>> Solar, atomic, or something else entirely?


> Solar. It's all mechanical. No electronics.

Just to clarify, it is a digital mechanical device with a tenth-Hz "clock" in the computer science sense. It relies on an external analog sync as the Sun crosses the local meridian. The clock discipline can withstand a stretch of tens of thousands of overcast days by, among other things, carefully correcting for the equation of time.


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