Re: [time-nuts] Time Nuts at PTTI this past week
I remember a brief interview with a person who coordinates G info for the military. They have detailed maps of g effects around the world (useful for targetting missiles, apparently) but the work is classified. jay John Miles wrote: >It is surprisingly hard to get a straight answer about what happens to g on >a mountain (http://www.newton.dep.anl.gov/askasci/phy00/phy00905.htm). I >guess it's in the paper, but what source(s) did you use to arrive at the >1.5E-13 figure? > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GMT vs. UTC
James Maynard wrote: >Magnus Danielson wrote: > > > >>I would feel more comfortable if I knew that the official time (and those the >>legal time) would be some 1h multiple of UTC and that this 1h multiple is >>precisely defined for normal and summer time. >> >> > >It all depends on your local time zone. Not all time zones are offset >from UTC by integral multiples of 1 h. > >Chatham Islands time = UTC + 12 h 45 min (when on standard time) >Chatham Islands time = UTC + 13 h 45 m (when on summer time) > > > I thought my 'world time' watch was cool because it took into account the x.5 h time zones. They apparently still missed something. ) jay ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Features of a Precision Clock?
I have found this utterly fascinating.I've learned a great deal from this exchange. Jay Bill Hawkins wrote: >O >Since control is not precise, the subject is probably off >topic for this list. > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Article on quartz locking pendulum clock
Oh the nostalgia of those old Amateur Scientist articles. That alone is worth it. I remember as a kid trying to follow those instructions with limited supplies in my house. Jay Dr. David Kirkby wrote: >A list member kindly snet me a copy of the article from about quartz >locking a pendulum clock. It uses an electromagnet and a magnet on the >pendulum. > >I have scanned this at 300 dpi grayscale and converted to pdf. It may be >found at: > >http://www.g8wrb.org/useful-stuff/time/pendulum+quartz.pdf > >The file size is 17460323 bytes (16.7 MB) >The MD5 checksum is AB0E083B25D8438604D83DFC6B2CB38F > >dave k > >___ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Newbie questions, UTC vs. Greenwich
Lots of discussion here: http://www.ucolick.org/~sla/leapsecs/timescales.html Alan Kruse wrote: > Hi, > > > >What is the difference between Universal Coordinated Time (UTC) and >Greenwich Mean Time? > > > >Thanks, > > > >Al >___ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Quartz assisted pendulum clock.
A pendulum is constant in the absence of forcing (which is why deadbeat and grasshopper escapements are so successful), however it's rate can be momentarily altered by any kind of pulse. John Miles wrote: >> >> > >Right, or whether there's an electromagnet that gives it a push or a pull >once in awhile. > >-- john, KE5FX > > > >___ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Quartz assisted pendulum clock.
You are correct, but if callibration weights were added above or below the CG, they would have an effect. [different subject] I cannot confirm that IBM story, however remember that IBM was making master/slave clocks for decades before they got in the computer business. Perhaps that is where this story (or legend) originated. Chuck Harris wrote: > >A pendulum swings at the same rate, regardless of its weight. The controlling >feature is the length of the pendulum. > >A balance wheel, is a different beast, because the weight of the wheel is >balanced against the tension of the spring. > >-Chuck > >___ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Three subjects.
Yes, there were a similar product produced for schools and offices that synchronized the clocks to a master kept in the office though it lacked the function for bringing a generator output into line. For a time, before quartz, the very best observatory clocks were a pendulum variety with a 'master' pendulum in a vacuum case and a 'slave' pendulum in a conventional clock. The slave was set very slightly slower and pulled into line from a periodic pulse from the master (which was kept running with electrical impulses). I would guess that there was a Amateur Scientist article covering something like this, though with the refinement of pendulum longcase (grandfather) clocks by that time in history, I don't know as any amateur modifications would actually improve timekeeping. Hal Murray wrote: >>http://www.telechron.com/ >> >> > >Neat. Thanks. > >I think we had one like that back in grade school. That was a long time ago. > > >There was an article in Scientific American 20 or 30 years ago. The idea was >to make an old grandfather clock keep very good time by adding a magnet to >the pendulum so you could gently push/pull it. > >Anybody remember that one? Anybody build one? > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Three subjects.
Have you seen this http://www.telechron.com/ Jim Miller wrote: >On Jan 3, 2006, at 3:32 PM, Dennis O'Keefe wrote: > > > >>The Accutron was advertised to be accurate to a minute a month. >>Mine was +47 >>1/2 seconds at the end of the month. I no longer have that watch. >> >> > >My father used to work at a small (200 MW) municipal power plant and >when I was young (1970s) I would occasionally go along with him to >work. They had a Telechron clock and an Accutron right next to each >other in the control room next to the synchroscope meter for each >boiler/generator unit. The Telechron with its synchronous AC motor >was hooked to the generator main output and the Accutron was >naturally a "standalone" device. When off the grid they would trim >the steam throttles to adjust the frequency of their generators to >make the Telechron stay in agreement with the Accutron. Once it was >time to go back on the grid they would use the synchroscope to assure >that they were in phase with the grid. As you can imagine it would >be a very, very bad day if they were to close the tie breaker to the >grid while out of phase. The accutron / telechron arrangement was to >keep the clocks in the town accurate during the off-grid interval. > >Jim > > >___ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Interesting web article
I don't know if this link has been posted before but I found it interesting. Long discussion of quartz oscillators (including design and problems) and discussion of the current quantum methods as well. http://www.ieee-uffc.org/freqcontrol/tutorials/vig2/tutorial2_files/frame.htm ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
