Re: [time-nuts] Shortt Clock Recent Measurements
The eccentric English physicist Boys made quartz fibres by attaching one end to a crossbow bolt, heating the middle and then firing the bolt, at what I have been unable to determine. He used this to measure the gravitational constant by suspending iron spheres from the resultant fibre, which of course was amazingly strong for it's diameter. Myself I'd use a pneumatic cannon, since I have one, rather than a crossbow. Tom Harris celephi...@gmail.com On 11 December 2013 15:55, Jim Lux jim...@earthlink.net wrote: On 12/10/13 5:57 PM, Don Latham wrote: I always thought invar was the magic metal. Quartz rod? You can get those at some reasonable cost? 12 mm dia fused qtz, about $10 per ft, so under $40 to get going, assuming 4 or 5 to learn how to do it right. It does break... 12.7 mm dia Invar 1 m long is $530 Amazing, and quartz is better (A single crystal would cost a pretty penny. I'm not sure a crystal that long can be drawn using a zone furnace). Pyrex is also available. These are quick 'net prices. John Strong's book tells how to make thin high-q fused silica fibers with an appropriate burner. Just the thing for your torsion balance, etc. back in the day when a self respecting experimental physicist built their own equipment. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
There is a good writeup of the Dicke switch in Horowitz Hill The Art of Electronics, since Horiwitz is a radioastronomer of note. I've just bought my daughter a copy for Xmas, poor girl, she wants to be an engineer... Tom Harris celephi...@gmail.com On 11 December 2013 13:02, Don Latham d...@montana.com wrote: Brooke Clarke PS When I was working in microwave electronics we talked about the Dicke radiometer, but I haven't found any definitive web page about that. Gotta look at Radio Astronomy pages and history. Actually, Dicke was using that radiometer to look for the microwave cosmic background, but the bell Labs guys had the big antenna. size matters :-) -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
:Hi Tom: I can't find anything in the Table of Contents or in the index. Can you tell me the page or title of the writeup? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tom Harris wrote: There is a good writeup of the Dicke switch in Horowitz Hill The Art of Electronics, since Horiwitz is a radioastronomer of note. I've just bought my daughter a copy for Xmas, poor girl, she wants to be an engineer... Tom Harris celephi...@gmail.com On 11 December 2013 13:02, Don Latham d...@montana.com wrote: Brooke Clarke PS When I was working in microwave electronics we talked about the Dicke radiometer, but I haven't found any definitive web page about that. Gotta look at Radio Astronomy pages and history. Actually, Dicke was using that radiometer to look for the microwave cosmic background, but the bell Labs guys had the big antenna. size matters :-) -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
On 12/12/13 4:28 PM, Tom Harris wrote: The eccentric English physicist Boys made quartz fibres by attaching one end to a crossbow bolt, heating the middle and then firing the bolt, at what I have been unable to determine. He used this to measure the gravitational constant by suspending iron spheres from the resultant fibre, which of course was amazingly strong for it's diameter. Myself I'd use a pneumatic cannon, since I have one, rather than a crossbow. A crossbow is, shall we say, more English, although perhaps historically, a longbow might be more significant. Was that the same Boys who invented the Boys camera used to take lightning photographs? It's a sort of rotating drum streak camera. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
It's in the section on lock in amplifiers I think. The switch has a clever 3 way action I think but I can't quire remember how it works. I do remember thinking how ingenious it was at the time, since I was designing lock in amplifiers for detecting optical absorbance over 10cm path lengths using photodiodes, instead of the tradional PMTs. Tom Harris celephi...@gmail.com On 13 December 2013 14:19, Brooke Clarke bro...@pacific.net wrote: :Hi Tom: I can't find anything in the Table of Contents or in the index. Can you tell me the page or title of the writeup? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tom Harris wrote: There is a good writeup of the Dicke switch in Horowitz Hill The Art of Electronics, since Horiwitz is a radioastronomer of note. I've just bought my daughter a copy for Xmas, poor girl, she wants to be an engineer... Tom Harris celephi...@gmail.com On 11 December 2013 13:02, Don Latham d...@montana.com wrote: Brooke Clarke PS When I was working in microwave electronics we talked about the Dicke radiometer, but I haven't found any definitive web page about that. Gotta look at Radio Astronomy pages and history. Actually, Dicke was using that radiometer to look for the microwave cosmic background, but the bell Labs guys had the big antenna. size matters :-) -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Jim Lux The very one... Don Was that the same Boys who invented the Boys camera used to take lightning photographs? It's a sort of rotating drum streak camera. ___ 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. -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements (Brooke Clarke)
A second on the book. Wonderful read. His method for cleaning out an optical interferometer was delightful. Also, the 'standard' formal evening dress in that community became what we now know as the Tuxedo. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of johncr...@aol.com Sent: Tuesday, December 10, 2013 19:57 To: time-nuts@febo.com Subject: Re: [time-nuts] Shortt Clock Recent Measurements (Brooke Clarke) It is not surprising that one can find little about Alfred Loomis. He was notoriously publicity shy and never gave interviews. Before his death he had much of research material disposed of. However the private lab he created at Tuxedo Park NY. was a gathering place for all of the key scientists of his time. He used his considerable fortune to fund the research of promising scientists. If anything was hot in physics in the 30's and early 40's he was there. For example he is in a photo taken at the early Berkley Summer Study where the greats in physics gathered to determine the feasibility of the A-Bomb. He was probably the last of the great Gentleman Scientists. A great read is Tuxedo Park by Jennet Conant (yep of the same family) first published in 2002. I read a borrowed copy then. And with all the discussion about him, I recalled the book. I tried Amazon and just got a Kindle edition. (The amazon listing mentions Oppenheimer, but the book is all about Loomis). Read the reviews if interested. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
In message d82c3cbd5688ab036d49d2d32515a859.squir...@webmail.montana.com, Do n Latham writes: I think if I were to start designing, I'd use a quartz rod instead, I'd go for SiC, like they did for the optics bench in the GAIA satellite -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
In message 82901.1386754...@critter.freebsd.dk, Poul-Henning Kamp writes: In message d82c3cbd5688ab036d49d2d32515a859.squir...@webmail.montana.com, Do n Latham writes: I think if I were to start designing, I'd use a quartz rod instead, I'd go for SiC, like they did for the optics bench in the GAIA satellite ... I guess I should add: GAIA is currently scheduled for launch on the 19th, and it has very stringent requirements for precise on-board time, served by a Rb clock. Gaia homepage: http://www.cosmos.esa.int/web/gaia About the clock requirements: http://www.congrex.nl/EFTF_Proceedings/Papers/Session_15_GNSS_Timing_2/15_01_Droz_Fabien.pdf -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements (Brooke Clarke)
I stumbled across a paperback copy also and was impressed also. The funding and wide range of experimentation he did. Regards Paul. On Wed, Dec 11, 2013 at 3:12 AM, DaveH i...@blackmountainforge.com wrote: A second on the book. Wonderful read. His method for cleaning out an optical interferometer was delightful. Also, the 'standard' formal evening dress in that community became what we now know as the Tuxedo. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of johncr...@aol.com Sent: Tuesday, December 10, 2013 19:57 To: time-nuts@febo.com Subject: Re: [time-nuts] Shortt Clock Recent Measurements (Brooke Clarke) It is not surprising that one can find little about Alfred Loomis. He was notoriously publicity shy and never gave interviews. Before his death he had much of research material disposed of. However the private lab he created at Tuxedo Park NY. was a gathering place for all of the key scientists of his time. He used his considerable fortune to fund the research of promising scientists. If anything was hot in physics in the 30's and early 40's he was there. For example he is in a photo taken at the early Berkley Summer Study where the greats in physics gathered to determine the feasibility of the A-Bomb. He was probably the last of the great Gentleman Scientists. A great read is Tuxedo Park by Jennet Conant (yep of the same family) first published in 2002. I read a borrowed copy then. And with all the discussion about him, I recalled the book. I tried Amazon and just got a Kindle edition. (The amazon listing mentions Oppenheimer, but the book is all about Loomis). Read the reviews if interested. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Here's a well-written introduction to time frequency article. Both a good overview for any newcomer to the group and some addition photos and recent information for the rest of us: Time - the SI Base Unit Second, by Andreas Bauch (PTB, 2012) http://www.ptb.de/cms/fileadmin/internet/fachabteilungen/abteilung_4/4.4_zeit_und_frequenz/pdf/2012_Bauch_PTBM_125a_en.pdf Brooke -- figure 2 is the Scheibe and Adelsberger plot I mentioned showing seasonal irregularity in earth rotation relative to laboratory quartz clocks, from 1934 to 1940. I'm tracking down evidence of earlier work. Attila -- figure 5 is another example of a composite ADEV plot showing cesium, masers, etc. /tvb ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Here's a specific reference from 1931: http://adsabs.harvard.edu/full/1931MNRAS..91..575B Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Tuesday, December 10, 2013 12:55 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements Hi Tom: The way I read the comment about detecting the influence of the Moon was that it was discovered in 1984, but I was under the impression that Loomis found it long before. I looked on other Wiki pages and did not see on any of the them information about Loomis and the effect of the Moon on pendulum clocks. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Sorry, I should have read the article. It was found by asking for Loomis moon pendulum The article is fascinating to Shortt clock fans, but does not mention the moon. Use their page back to get the whole article. Bill Hawkins -Original Message- From: Bill Hawkins [mailto:b...@iaxs.net] Sent: Tuesday, December 10, 2013 9:54 AM To: 'Discussion of precise time and frequency measurement' Subject: RE: [time-nuts] Shortt Clock Recent Measurements Here's a specific reference from 1931: http://adsabs.harvard.edu/full/1931MNRAS..91..575B Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Tuesday, December 10, 2013 12:55 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements Hi Tom: The way I read the comment about detecting the influence of the Moon was that it was discovered in 1984, but I was under the impression that Loomis found it long before. I looked on other Wiki pages and did not see on any of the them information about Loomis and the effect of the Moon on pendulum clocks. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Its not in the Loomis article, lunar influence is in the Brown and Brouwer analysis, beginning on pg. 581. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bill Hawkins Sent: Tuesday, December 10, 2013 11:12 AM To: 'Bill Hawkins'; 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Shortt Clock Recent Measurements Sorry, I should have read the article. It was found by asking for Loomis moon pendulum The article is fascinating to Shortt clock fans, but does not mention the moon. Use their page back to get the whole article. Bill Hawkins -Original Message- From: Bill Hawkins [mailto:b...@iaxs.net] Sent: Tuesday, December 10, 2013 9:54 AM To: 'Discussion of precise time and frequency measurement' Subject: RE: [time-nuts] Shortt Clock Recent Measurements Here's a specific reference from 1931: http://adsabs.harvard.edu/full/1931MNRAS..91..575B Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Tuesday, December 10, 2013 12:55 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements Hi Tom: The way I read the comment about detecting the influence of the Moon was that it was discovered in 1984, but I was under the impression that Loomis found it long before. I looked on other Wiki pages and did not see on any of the them information about Loomis and the effect of the Moon on pendulum clocks. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
There should be some error if you are to buy into Dr Allan's new gravitational theory. Has anyone attempted to duplicate his experiments concerning high energy density effects on a Shortt Clock? I posted a link to Dr Allan's web site last night on this thread. Thomas Knox From: t...@leapsecond.com Date: Mon, 9 Dec 2013 18:39:26 -0800 To: time-nuts@febo.com Subject: Re: [time-nuts] Shortt Clock Recent Measurements Brooke, Not sure what you find in error; please explain. I have all the Shortt info you need. Not all of it is for Wikipedia; contact me off-line. Just got back from the CalTech Time Symposium: http://leapsecond.com/nawcc2013/ The conjecture about tides is explained in great detail here: http://leapsecond.com/hsn2006/ Meanwhile, see: http://leapsecond.com/pend/shortt/ http://leapsecond.com/pend/shortt/1931-RAS-Analysis-Loomis-Chronograph-Brown-Brouwer.pdf http://leapsecond.com/pend/shortt/1931-RAS-Precise-Measurement-Time-Loomis.pdf /tvb (i5s) On Dec 9, 2013, at 5:02 PM, Brooke Clarke bro...@pacific.net wrote: Hi: The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Hi Brooke, The wiki page is correct. The heading is Recent Measurements and Pierre Boucheron's 1984 effort certainly qualifies. Note the wiki doesn't claim Boucheron was the first. In fact, even 30 years old, it is still the most recent, and the only Shortt experiment for which we have raw data. See http://leapsecond.com/pend/shortt/ for details. One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. I mean, if you look at the list of who received the one hundred Shortt's that were manufactured, many laboratories had more than one, not to mention the ones that William Shortt himself owned at the factory. Certainly there was a lot of time measurement going on in the 20's and 30's. It would take a lot of work to uncover what was known by whom and when. Or who published first or not. I think Loomis took it a wonderful extreme with his spark chronograph and quartz oscillator via telephone time transfer setup. And that be bought three clocks at once is classic and inspiring to any time nut! So I agree, Loomis deserves mention on the Shortt wiki page. Unrelated to gravity and tides, is the role that vacuum pendulum and ovenized quartz clocks had in confirming that earth rotation was itself irregular at the millisecond level. Credit for that usually goes to Scheibe and Adelsberger in the late 30's, not Shortt or Loomis. And that of course blends into the story of the leap second... See my scan/OCR historical pendulum collection: http://leapsecond.com/pend/pdf/ And my own precision pendulum-nut articles: http://leapsecond.com/hsn2006/ Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. /tvb ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. Just FYI: During my reading of BSTJ I noticed a reference to a paper by Loomis and Marrington at bottom of p4: www3.alcatel-lucent.com/bstj/vol11-1932/articles/bstj11-2-318.pdf -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
FWIW Let me just second Tom's last comment: Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. About 2 years ago the Time Nut in me became very interested in pendulum clocks that were made in my home town in Vermont going back as far as 1797. I now own several and a project is to take one of them that has a dead-beat escapement (often noted for its better accuracy display of seconds with an 10 inch sweep hand in its day) into the 21st century with frequency locking of the pendulum to the 1PPS from one of my GPS receivers. AlsoAn antique clock dealer who is friend of mine was well pleased with TVB's talk at a recent time conference on the West Coast. So it is a mix of old and new for me at this point. Apologies if this goes OT. Regards, -Brian, WA1ZMS/4 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Tuesday, December 10, 2013 5:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_ measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Hi Brooke, The wiki page is correct. The heading is Recent Measurements and Pierre Boucheron's 1984 effort certainly qualifies. Note the wiki doesn't claim Boucheron was the first. In fact, even 30 years old, it is still the most recent, and the only Shortt experiment for which we have raw data. See http://leapsecond.com/pend/shortt/ for details. One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. I mean, if you look at the list of who received the one hundred Shortt's that were manufactured, many laboratories had more than one, not to mention the ones that William Shortt himself owned at the factory. Certainly there was a lot of time measurement going on in the 20's and 30's. It would take a lot of work to uncover what was known by whom and when. Or who published first or not. I think Loomis took it a wonderful extreme with his spark chronograph and quartz oscillator via telephone time transfer setup. And that be bought three clocks at once is classic and inspiring to any time nut! So I agree, Loomis deserves mention on the Shortt wiki page. Unrelated to gravity and tides, is the role that vacuum pendulum and ovenized quartz clocks had in confirming that earth rotation was itself irregular at the millisecond level. Credit for that usually goes to Scheibe and Adelsberger in the late 30's, not Shortt or Loomis. And that of course blends into the story of the leap second... See my scan/OCR historical pendulum collection: http://leapsecond.com/pend/pdf/ And my own precision pendulum-nut articles: http://leapsecond.com/hsn2006/ Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. /tvb ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Brian and Tom: I second as well. It's important to be aware of the past. Somewhere around here is a 4 ft length of Invar, 1/2 in. diameter. It was supposed to be a pendulum rod. However, I did read that Invar displays rearrangement noise of some kind. Kinda like the jumps in a quartz element? I think if I were to start designing, I'd use a quartz rod instead, coefficient of thermal expansion is smaller. I'll bet that a large majority of time-nuts have at least read about pendulum timekeepers... The Smithsonian has a Schortt clock, as well as a couple of others. I am sad that they aren't running. Don Brian, WA1ZMS FWIW Let me just second Tom's last comment: Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. About 2 years ago the Time Nut in me became very interested in pendulum clocks that were made in my home town in Vermont going back as far as 1797. I now own several and a project is to take one of them that has a dead-beat escapement (often noted for its better accuracy display of seconds with an 10 inch sweep hand in its day) into the 21st century with frequency locking of the pendulum to the 1PPS from one of my GPS receivers. AlsoAn antique clock dealer who is friend of mine was well pleased with TVB's talk at a recent time conference on the West Coast. So it is a mix of old and new for me at this point. Apologies if this goes OT. Regards, -Brian, WA1ZMS/4 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Tuesday, December 10, 2013 5:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_ measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Hi Brooke, The wiki page is correct. The heading is Recent Measurements and Pierre Boucheron's 1984 effort certainly qualifies. Note the wiki doesn't claim Boucheron was the first. In fact, even 30 years old, it is still the most recent, and the only Shortt experiment for which we have raw data. See http://leapsecond.com/pend/shortt/ for details. One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. I mean, if you look at the list of who received the one hundred Shortt's that were manufactured, many laboratories had more than one, not to mention the ones that William Shortt himself owned at the factory. Certainly there was a lot of time measurement going on in the 20's and 30's. It would take a lot of work to uncover what was known by whom and when. Or who published first or not. I think Loomis took it a wonderful extreme with his spark chronograph and quartz oscillator via telephone time transfer setup. And that be bought three clocks at once is classic and inspiring to any time nut! So I agree, Loomis deserves mention on the Shortt wiki page. Unrelated to gravity and tides, is the role that vacuum pendulum and ovenized quartz clocks had in confirming that earth rotation was itself irregular at the millisecond level. Credit for that usually goes to Scheibe and Adelsberger in the late 30's, not Shortt or Loomis. And that of course blends into the story of the leap second... See my scan/OCR historical pendulum collection: http://leapsecond.com/pend/pdf/ And my own precision pendulum-nut articles: http://leapsecond.com/hsn2006/ Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. /tvb ___ 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. -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846
Re: [time-nuts] Shortt Clock Recent Measurements
Been reading and not getting tangled up. Agree that it seems like a reasonable subject. Though I have no pendulum clocks. I was struck by their beauty up in Canada at TVAs television studios. On the wall was this amazing clock on a huge slab of metal. All it needed was a battery. Other then that it was clean and gently pushing the pendulum seemed to make it work. It was to go into there historical museum someday. I always thought invar was the magic metal. Quartz rod? You can get those at some reasonable cost? What I am curious about is there a wear mechanism on these really good clocks. Does the pendulum just swing on a bending piece of metal or on a bearing? To the technical side isn't it sort of cheating the wonder of the clock using gps correction. I mean at that point there is no point. I am asking these questions because its sort of the thing I would not mind crafting. Regards Paul. WB8TSL On Tue, Dec 10, 2013 at 7:15 PM, Don Latham d...@montana.com wrote: Brian and Tom: I second as well. It's important to be aware of the past. Somewhere around here is a 4 ft length of Invar, 1/2 in. diameter. It was supposed to be a pendulum rod. However, I did read that Invar displays rearrangement noise of some kind. Kinda like the jumps in a quartz element? I think if I were to start designing, I'd use a quartz rod instead, coefficient of thermal expansion is smaller. I'll bet that a large majority of time-nuts have at least read about pendulum timekeepers... The Smithsonian has a Schortt clock, as well as a couple of others. I am sad that they aren't running. Don Brian, WA1ZMS FWIW Let me just second Tom's last comment: Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. About 2 years ago the Time Nut in me became very interested in pendulum clocks that were made in my home town in Vermont going back as far as 1797. I now own several and a project is to take one of them that has a dead-beat escapement (often noted for its better accuracy display of seconds with an 10 inch sweep hand in its day) into the 21st century with frequency locking of the pendulum to the 1PPS from one of my GPS receivers. AlsoAn antique clock dealer who is friend of mine was well pleased with TVB's talk at a recent time conference on the West Coast. So it is a mix of old and new for me at this point. Apologies if this goes OT. Regards, -Brian, WA1ZMS/4 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Tuesday, December 10, 2013 5:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_ measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Hi Brooke, The wiki page is correct. The heading is Recent Measurements and Pierre Boucheron's 1984 effort certainly qualifies. Note the wiki doesn't claim Boucheron was the first. In fact, even 30 years old, it is still the most recent, and the only Shortt experiment for which we have raw data. See http://leapsecond.com/pend/shortt/ for details. One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. I mean, if you look at the list of who received the one hundred Shortt's that were manufactured, many laboratories had more than one, not to mention the ones that William Shortt himself owned at the factory. Certainly there was a lot of time measurement going on in the 20's and 30's. It would take a lot of work to uncover what was known by whom and when. Or who published first or not. I think Loomis took it a wonderful extreme with his spark chronograph and quartz oscillator via telephone time transfer setup. And that be bought three clocks at once is classic and inspiring to any time nut! So I agree, Loomis deserves mention on the Shortt wiki page. Unrelated to gravity and tides, is the role that vacuum pendulum and ovenized quartz clocks had in confirming that earth rotation was itself irregular at the millisecond level. Credit for that usually goes to Scheibe and Adelsberger in the late 30's, not Shortt or Loomis. And that of course blends into the story of the leap second... See my scan/OCR historical
Re: [time-nuts] Shortt Clock Recent Measurements
Hi Tom: Here's a web page that has an annotated list of some patents applicable to pendulums: http://www.prc68.com/I/Pendulums.shtml Many of the early gravity meters were just pendulums, then came the falling corner reflectors. There are a couple of patents by Dicke and this one: 3036465 http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=3036465 Gravity Meter, It may be close to your Dream pendulum has a Q of about a million. PS When I was working in microwave electronics we talked about the Dicke radiometer, but I haven't found any definitive web page about that. It was just a SPDT switch on the input to a low noise amplifier that alternated between an antenna and a termination at a known temperature (kTBR). One of our employes used that idea with a piston driven by a PN code to change the input pressure to a steam generating plant and using a correlation function on the electrical output electrical power to get the plant's impulse response. http://en.wikipedia.org/wiki/Lock-in_amplifier The lock-in amplifier is commonly believed to be invented by Princeton University http://en.wikipedia.org/wiki/Princeton_University physicist Robert H. Dicke http://en.wikipedia.org/wiki/Robert_H._Dicke who founded the company Princeton Applied Research (PAR) to market the product. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tom Van Baak wrote: The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Hi Brooke, The wiki page is correct. The heading is Recent Measurements and Pierre Boucheron's 1984 effort certainly qualifies. Note the wiki doesn't claim Boucheron was the first. In fact, even 30 years old, it is still the most recent, and the only Shortt experiment for which we have raw data. See http://leapsecond.com/pend/shortt/ for details. One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. I mean, if you look at the list of who received the one hundred Shortt's that were manufactured, many laboratories had more than one, not to mention the ones that William Shortt himself owned at the factory. Certainly there was a lot of time measurement going on in the 20's and 30's. It would take a lot of work to uncover what was known by whom and when. Or who published first or not. I think Loomis took it a wonderful extreme with his spark chronograph and quartz oscillator via telephone time transfer setup. And that be bought three clocks at once is classic and inspiring to any time nut! So I agree, Loomis deserves mention on the Shortt wiki page. Unrelated to gravity and tides, is the role that vacuum pendulum and ovenized quartz clocks had in confirming that earth rotation was itself irregular at the millisecond level. Credit for that usually goes to Scheibe and Adelsberger in the late 30's, not Shortt or Loomis. And that of course blends into the story of the leap second... See my scan/OCR historical pendulum collection: http://leapsecond.com/pend/pdf/ And my own precision pendulum-nut articles: http://leapsecond.com/hsn2006/ Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. /tvb ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
I always thought invar was the magic metal. Quartz rod? You can get those at some reasonable cost? 12 mm dia fused qtz, about $10 per ft, so under $40 to get going, assuming 4 or 5 to learn how to do it right. It does break... 12.7 mm dia Invar 1 m long is $530 Amazing, and quartz is better (A single crystal would cost a pretty penny. I'm not sure a crystal that long can be drawn using a zone furnace). Pyrex is also available. These are quick 'net prices. What I am curious about is there a wear mechanism on these really good clocks. Does the pendulum just swing on a bending piece of metal or on a bearing? most on bending metal. The 100 lb weight Foucault pendulum at Griffith Observatory that I liked as a kid, 65 yr ago, simply had a piano wire chucked in a pin vise. Lasted until now, AFIK. Qtz rod would require some kind of epoxied cap etc. There are also knife edge bearings and the like. The Q of the pendulum depends in part on the energy lost in the support hinge. OTH, some energy has to be lost in order to quell possible chaotic modes (that's my opinion and I'm stickin' to it) To the technical side isn't it sort of cheating the wonder of the clock using gps correction. Yep. I mean at that point there is no point. I am asking these questions because its sort of the thing I would not mind crafting. Regards Paul. WB8TSL On Tue, Dec 10, 2013 at 7:15 PM, Don Latham d...@montana.com wrote: Brian and Tom: I second as well. It's important to be aware of the past. Somewhere around here is a 4 ft length of Invar, 1/2 in. diameter. It was supposed to be a pendulum rod. However, I did read that Invar displays rearrangement noise of some kind. Kinda like the jumps in a quartz element? I think if I were to start designing, I'd use a quartz rod instead, coefficient of thermal expansion is smaller. I'll bet that a large majority of time-nuts have at least read about pendulum timekeepers... The Smithsonian has a Schortt clock, as well as a couple of others. I am sad that they aren't running. Don Brian, WA1ZMS FWIW Let me just second Tom's last comment: Some of you readers might wonder why in this GPS age, two time nuts, each with plenty of atomic clocks at home, would be talking about vintage pendulum clocks. It turns out that pendulum clocks are still extremely interesting timekeepers, from an experimental, scientific, and historical perspective. About 2 years ago the Time Nut in me became very interested in pendulum clocks that were made in my home town in Vermont going back as far as 1797. I now own several and a project is to take one of them that has a dead-beat escapement (often noted for its better accuracy display of seconds with an 10 inch sweep hand in its day) into the 21st century with frequency locking of the pendulum to the 1PPS from one of my GPS receivers. AlsoAn antique clock dealer who is friend of mine was well pleased with TVB's talk at a recent time conference on the West Coast. So it is a mix of old and new for me at this point. Apologies if this goes OT. Regards, -Brian, WA1ZMS/4 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Tuesday, December 10, 2013 5:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Shortt Clock Recent Measurements The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_ measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Hi Brooke, The wiki page is correct. The heading is Recent Measurements and Pierre Boucheron's 1984 effort certainly qualifies. Note the wiki doesn't claim Boucheron was the first. In fact, even 30 years old, it is still the most recent, and the only Shortt experiment for which we have raw data. See http://leapsecond.com/pend/shortt/ for details. One could try claiming that Loomis was the first to make detailed measurements of a Shortt, but it would take some digging to prove he was first and not just one of the first. I mean, if you look at the list of who received the one hundred Shortt's that were manufactured, many laboratories had more than one, not to mention the ones that William Shortt himself owned at the factory. Certainly there was a lot of time measurement going on in the 20's and 30's. It would take a lot of work to uncover what was known by whom and when. Or who published first or not. I think Loomis took it a wonderful extreme with his spark chronograph and quartz oscillator via telephone time transfer setup. And that be bought three clocks at once is classic
Re: [time-nuts] Shortt Clock Recent Measurements
Brooke Clarke PS When I was working in microwave electronics we talked about the Dicke radiometer, but I haven't found any definitive web page about that. Gotta look at Radio Astronomy pages and history. Actually, Dicke was using that radiometer to look for the microwave cosmic background, but the bell Labs guys had the big antenna. size matters :-) -- The power of accurate observation is commonly called cynicism by those who have not got it. -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements (Brooke Clarke)
It is not surprising that one can find little about Alfred Loomis. He was notoriously publicity shy and never gave interviews. Before his death he had much of research material disposed of. However the private lab he created at Tuxedo Park NY. was a gathering place for all of the key scientists of his time. He used his considerable fortune to fund the research of promising scientists. If anything was hot in physics in the 30's and early 40's he was there. For example he is in a photo taken at the early Berkley Summer Study where the greats in physics gathered to determine the feasibility of the A-Bomb. He was probably the last of the great Gentleman Scientists. A great read is Tuxedo Park by Jennet Conant (yep of the same family) first published in 2002. I read a borrowed copy then. And with all the discussion about him, I recalled the book. I tried Amazon and just got a Kindle edition. (The amazon listing mentions Oppenheimer, but the book is all about Loomis). Read the reviews if interested. - 73 john k6iql ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
On 12/10/13 5:57 PM, Don Latham wrote: I always thought invar was the magic metal. Quartz rod? You can get those at some reasonable cost? 12 mm dia fused qtz, about $10 per ft, so under $40 to get going, assuming 4 or 5 to learn how to do it right. It does break... 12.7 mm dia Invar 1 m long is $530 Amazing, and quartz is better (A single crystal would cost a pretty penny. I'm not sure a crystal that long can be drawn using a zone furnace). Pyrex is also available. These are quick 'net prices. John Strong's book tells how to make thin high-q fused silica fibers with an appropriate burner. Just the thing for your torsion balance, etc. back in the day when a self respecting experimental physicist built their own equipment. ___ 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] Shortt Clock Recent Measurements
Hi: The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
I thought I needed to throw this in the mix. http://www.allanstime.com/Research/Pendulum/index.html Enjoy. Thomas Knox Date: Mon, 9 Dec 2013 17:02:22 -0800 From: bro...@pacific.net To: time-nuts@febo.com Subject: [time-nuts] Shortt Clock Recent Measurements Hi: The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Brooke, Not sure what you find in error; please explain. I have all the Shortt info you need. Not all of it is for Wikipedia; contact me off-line. Just got back from the CalTech Time Symposium: http://leapsecond.com/nawcc2013/ The conjecture about tides is explained in great detail here: http://leapsecond.com/hsn2006/ Meanwhile, see: http://leapsecond.com/pend/shortt/ http://leapsecond.com/pend/shortt/1931-RAS-Analysis-Loomis-Chronograph-Brown-Brouwer.pdf http://leapsecond.com/pend/shortt/1931-RAS-Precise-Measurement-Time-Loomis.pdf /tvb (i5s) On Dec 9, 2013, at 5:02 PM, Brooke Clarke bro...@pacific.net wrote: Hi: The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
Re: [time-nuts] Shortt Clock Recent Measurements
Hi Tom: The way I read the comment about detecting the influence of the Moon was that it was discovered in 1984, but I was under the impression that Loomis found it long before. I looked on other Wiki pages and did not see on any of the them information about Loomis and the effect of the Moon on pendulum clocks. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tom Van Baak (lab) wrote: Brooke, Not sure what you find in error; please explain. I have all the Shortt info you need. Not all of it is for Wikipedia; contact me off-line. Just got back from the CalTech Time Symposium: http://leapsecond.com/nawcc2013/ The conjecture about tides is explained in great detail here: http://leapsecond.com/hsn2006/ Meanwhile, see: http://leapsecond.com/pend/shortt/ http://leapsecond.com/pend/shortt/1931-RAS-Analysis-Loomis-Chronograph-Brown-Brouwer.pdf http://leapsecond.com/pend/shortt/1931-RAS-Precise-Measurement-Time-Loomis.pdf /tvb (i5s) On Dec 9, 2013, at 5:02 PM, Brooke Clarke bro...@pacific.net wrote: Hi: The Wiki page for the Shortt pendulum clock has a Recent Measurements (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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.
