IIRC, there was a large one at Weston Observatory (Boston College). But, it has been 40+ years since I was last there.
73, Dick, W1KSZ -----Original Message----- >From: Flemming Larsen <oz...@yahoo.dk> >Sent: Jul 22, 2010 1:47 AM >To: Discussion of precise time and frequency measurement <time-nuts@febo.com> >Subject: Re: [time-nuts] A different timenuts interest > >The Exploratorium at The Palace of Fine Arts in San Francisco had one of >these, and >may still have it. I haven't been there in a while and don't know the details. > >Nuts & Volts had a construction project for a continuously swinging pendulum >in their >September 2009 issue. It had a magnet at the end of the pendulum which >generated >a current in a coil mounted in the center of the base. A simple 2-transistor >circuit would >sense the pendulum swing and would generate a pulse in the same coil to >accelerate >the pendulum and keep it swinging in infinity, or until the battery died, >whichever came >first. > >Have you looked for ideas on Bryan Mumford's website? > >-- FL > > > >--- Den ons 21/7/10 skrev Morris Odell <vilgo...@bigpond.net.au>: > > >Fra: Morris Odell <vilgo...@bigpond.net.au> >Emne: [time-nuts] A different timenuts interest >Til: time-nuts@febo.com >Dato: onsdag 21. juli 2010 17.13 > > >Hi all, > >I have been asked to help with the construction of a Foucault pendulum. This >is a long pendulum which oscillates in a slow stately fashion in a fixed >plane which appears to move as the earth rotates. In reality the surrounding >environment is really moving relative to the plane of oscillation. > >The pendulum requires a sustaining system to compensate for the inevitable >energy loss with each swing. The system is located in the building and >therefore rotates relative to the pendulum. It needs to provide an impulse >which does not affect the plane of oscillation of the pendulum. I was >thinking of an electromagnet located below the centre of the swing which >would be pulsed appropriately as the bob passes over it. > >Has anyone here had any experience with such a system of have any >suggestions regarding the sustaining system? This is an interesting and >challenging project. > >Cheers, > >Morris > > > >_______________________________________________ >time-nuts mailing list -- time-nuts@febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > >_______________________________________________ >time-nuts mailing list -- time-nuts@febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.