Re: [Phys-L] Allan deviation

[Bernard Cleyet <bernardcleyet@redshift.com>]

On 2015, Jul 13, , at 08:11, Bill Norwood <bnorwood111@gmail.com> wrote:

> Many thanks, John, for that comprehensive explanation - I'll never look at
> a pendulum clock the same way again. Thank God they never had to go
> relativistic.


Well ….,   they have.  The MicroSet person sells a GPS adapter for the MS.  

 http://www.bmumford.com/mset/tech/gps/gps3.html  


And, IIRC, Mr. Mumford has resold Rb clocks, also.


To add to JD’s description:  Among the better formerly commercially available (I know of only two) clocks, the Synchronome uses a Zn sleeve.  The bob (originally 14 pound) rests on the sleeve, which then rests on the rating nut, which is on the end of the rod which is Invar. [This is similar to the Westminster clock I previously described.]  Modern horologists use silica.   However, even a recent article in the Horological Science Newsletter describes the method to remove the Invar shadow mask from a color kinescope.  An early ed. of the "Amateur Telescope Making” describes in detail (mechanical drawings, etc.) for those wishing to make one.  Also, IIRC, Mr. Mumford sold the support steel casting.  All the other materials being readily available.  


I have put my two tower clocks Allan deviation plots here, plus a more complete one from Tom Van Baak, here:  

http://www.cleyet.org/Pendula,%20Horological%20and%20Otherwise/Allan_deviation_tower_clocks.pdf  

bc forgot about the mercury temp. compensated clocks.  

p.s. An horologist in Utah showed me his and one is for sale in Pacific Grove (near where I reside).  Being not affluent I didn’t purchase it. (~ $1k).