Kent, from this descrition I gather that it's actaually only one clock, the one running in vacuum. The other clock is just for separation from the outside world in order to keep away all disturbances. Two questions arise for me:
- How is the vacuum pendulum adjusted in the first place to 200 us per day? By lots of trial an error, like me turning the nut on the pendulum's shaft end hopefully? Evacuate each time anew? - How is the motion of the pendulum detected without disturbance? You know, the old Heisenberg stuff... I can't imagine that mechanical contacts can be made completely free of reflexes to the pendulum. What kind of electric signals are transmitted in the "wires"? Peter Kent A. Reed schrieb: > Gentle persons: > > Gene Heskett asked me if there is a website describing the > Shortt-Synchronome clock I mentioned. One could start at > http://en.wikipedia.org/wiki/Shortt-Synchronome_clock which includes a > photograph of the one at NIST, No. 32 out of perhaps twice that many > sold to others. > > The reasons I fell in love with it include: > > 1) it consists of two pendulums, one running in a commonplace industrial > clock---the Synchronome time transmitter---and one running in a > vacuum---the Shortt free pendulum---cross-coupled electrically, that was > the most accurate pendulum clock in the world. It that was surpassed as > a time keeper only when crystal oscillators were put to the task. As a > physicist, I admired this ingenious coupled oscillator system and the > two men who invented it. > > 2) the clock is a precise time keeper but it is very imprecisely made. > Most of the Synchronome parts could be hacked out of pieces of flat and > round stock using saws, files, and drill bits (so why CNC? Because I say > so, that's why!). The principal difficulty with the Shortt free pendulum > is its vacuum encasement, and more than one amateur has simply ignored > that bit and lived with the loss of precision. Anyone looking at this > clock would think "Heck, I could do that." Compare it to the Riefler > observatory clock that hangs near the Shortt-Synchronome clock at NIST. > One look behind the Riefler dial or at the Riefler patent drawings would > convince one that this is a project for the masters (see, for example, > http://www.brown.edu/Departments/Physics/Ladd/instruments/clemens.html). > > 3) Frank Hope-Jones, the inventor and manufacturer of the Synchronome > clock and first the boss and then collaborator of William Hamilton > Shortt, the inventor of the cross-coupled free pendulum, explicitly > supported amateurs desiring to make their own copies of his clocks, even > providing kits of rough parts long ago. He openly published on all > aspects of his clocks. (He was also a shameless self-promoter as you'll > see in all his publications, but what the heck, nobody's perfect.) No > trade secrets and no patent trolls to deal with. The 500 or so members > of the Yahoo Synchronome Group now have wider interests than just the > Synchronome but many members own genuine Synchronome time transmitters > or have made their own. > > Regards, > Kent > > > > ------------------------------------------------------------------------------ > All the data continuously generated in your IT infrastructure > contains a definitive record of customers, application performance, > security threats, fraudulent activity, and more. Splunk takes this > data and makes sense of it. IT sense. And common sense. > http://p.sf.net/sfu/splunk-novd2d > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
