[time-nuts] Clock Calibration

scmcgrath at gmail.com scmcgrath at gmail.com
Sat Jan 29 17:16:04 UTC 2011

Ah now from time nuttery to horology. There are those of us who tinker with analog clocks as well...

Generally we 'beat' clocks against 'standard' clocks or more recently a pc application with a microphone over long periods of time generally at least a week and commonly a month.

Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: Chris Albertson <albertson.chris at gmail.com>
Sender: time-nuts-bounces at febo.com
Date: Thu, 27 Jan 2011 15:52:49 
To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] Clock Calibration

On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen <sandeenpa at yahoo.com> wrote:

> ...how the heck they were able to calibrate a clock to milliseconds per day back then?

Let it run for 1,000 days, then you only need to be able to measure to
the nearest second to get to ms per day.  Or maybe you can measure to
0.1 seconds so it only takes 100 days.

The trouble is that using this method you don't know the average
error.  A good example is an eccentric gear that makes a second hand
run fast then slow but if averaged over a long period is near perfect.
 I doubt they were able to catch stuff like that.

Chris Albertson
Redondo Beach, California

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