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Plot and as with

Best fit to data (blue line). Reference gradient (red lines):-8.6ms/day/mbar.
Going varies with pressure because of drag, added mass and buoyancy. Barometric compensator fitted 28 March 2010 should fix this.

Comments (see all | edit)

12 Aug 2020 [10:24]
winding by Kazuo Newcombe
05 Aug 2020 [12:31]
winding by John Aldridge
29 Jul 2020 [12:11]
top-up wind
24 Jul 2020 [16:22]
winding by Jessica Fintzen
18 Jul 2020 [19:02]
correcting quarter bells silencing wheel (Jessica Fintzen)
17 Jul 2020 [10:21]
trying to get quarters to ring again and top-up winding (Jessica Fintzen)
15 Jul 2020 [20:14]
winding by Jessica Fintzen
11 Jul 2020 [17:41]
stopped the fly for 6 seconds, edited last_drift (cd clocklogger/data, sudo systemctl stop clocklogger.service , nano last_drift changed to -2.8, ^x , sudo systemctl start clocklogger.service )
08 Jul 2020 [12:45]
winding by John Aldridge
01 Jul 2020 [10:05]
...and topped up after 11am BST
01 Jul 2020 [09:45]
winding by John Aldridge
25 Jun 2020 [11:17]
Newton clock wound
23 Jun 2020 [22:01]
winding, just after 11pm so next week can be on Wednesday anytime before noon
16 Jun 2020 [16:19]
winding by Jessica Fintzen
09 Jun 2020 [08:05]
winding by Jessica Fintzen
01 Jun 2020 [21:01]
25 May 2020 [15:18]
and also wound the Newton clock
25 May 2020 [15:17]
and then again left maintaining weight on after wind at 15h20. During wind it's about 5mW
25 May 2020 [14:45]
Then the maintaining weight on its own at around 14h46, total driving power around 12.6mW.
25 May 2020 [14:39]
top-up wind - and short experiment at 14h39 with extra 0.5kg on the maintaining weight. Total driving power is 14.3mW.
22 May 2020 [15:20]
ADJUST: +100ms/day to 15800 and top-up wind during Tea-Time Talk for DVRO
20 May 2020 [18:02]
top-up wind
19 May 2020 [12:20]
12 May 2020 [12:51]
winding. Also an experiment on the effect of night-time pigeons, simulated by using the maintaining weight. At 13h17 GMT I engaged the maintaining weight which stays engaged for about 5 minutes. Then at 13h37 I did the same but with 0.5kg of extra weight. Then the same at 13h47. Then again at 13h54.:15 but this time I did the wind from about one minute in - maybe this will be noticed.
05 May 2020 [17:07]
winding. Also tried to fix pi-clock5. SD card and USB stick both seem to be dead, probably caused by USB stick being full. I've put a new SD card in (with the help of John Aldridge who has reloaded the software). Now need to ask Jordan to re-register the machine for data uploads. By the way, formatting new SD cards is now really easy using the Raspberry Pi Imager [link]
30 Apr 2020 [13:00]
it looks like pi-clock5 has frozen. This does tower tilt from the spirit level bubble, and it records the bells for timing GCR.
28 Apr 2020 [11:00]
winding. Also wound the Newton clock. Not, it was nearly at the end - 30 days after its last wind. Useful to know - it probably lasts 31 days.
21 Apr 2020 [09:30]
ADJUST: -300ms/day to 15700. Top-up wind
18 Apr 2020 [14:26]
restart pi-clock10 which had stalled for some reason. top-up wind by Beatrice Hunt
17 Apr 2020 [15:07]
10 Apr 2020 [10:12]
checking the pendulum-case heater - it's hot. But it dislodged and now needs resoldering. Removed for repair, but in so doing I knocked pendulum in the process.
10 Apr 2020 [10:10]
shift regulation weights 40mm southwards to see if I can fix pendulum amplitude drops - maybe it's hitting something.
10 Apr 2020 [09:55]
ADJUST: +500ms/day to 16000. Winding (nb solo owing to COVID19)
03 Apr 2020 [14:35]
The clock had stopped shortly before noon: The pendulum was not swinging far enough anymore. Restarted the clock and used this occasion to wind it as well. (Jessica Fintzen)
03 Apr 2020 [10:42]
This appears to have been a pigeon event. Oh dear! Is the pigeon wire not working? [link]
29 Mar 2020 [07:23]
Also advanced and wound the Newton Clock in the Master's Lodge
29 Mar 2020 [07:18]
I shifted 10000 ms/day of regulation weights up onto the upper layer so that they can be as far north as possible, so as to minimize twist. I wonder of there's something wrong with the suspension, causing the twist?
29 Mar 2020 [07:15]
hour change for Summer Time, and winding solo owing to COVID 19 - definitely more fun with company!
29 Mar 2020 [07:15]
Procedure for advancing the clock on a Sunday Morning: Start at 08h02 (BST, ie new time). 1. insert the brass silencing devices for both quarters and strike. 2. With your left hand lift the escapement release never and allow the clock to run on, through 7.15, 7.30 and 7.45 (which will be silent) and then 8am will go through the motions of striking eight, but silently. 3. With your right hand grab the spinning fly shaft to slow the spin. 4. Come to a stop slightly beyond where you need to be and let go of the lever. 5. Now fine tune by stopping the fly for as long as is necessary to get the clock onto the correct time. 6. Now ermove the brass silencing devices. 7. Check that 8.15am quarters sound correctly. 9. All done!
29 Mar 2020 [07:05]
An experiment, shifting 5500 ms worth of regulation weights in five steps of 40mm from the north side of the pendulum shaft to the south side. The idea is to see how it affects pendulum twist. I suspect it's not a great experiemnt because the disturbance affects ampltude too and there's a strong coupling (linear?) between twist and amplitude.
29 Mar 2020 [06:48]
ADJUST: +150ms/day to 15500
24 Mar 2020 [12:04]
top-up wind
20 Mar 2020 [20:34]
winding by Jessica Fintzen
19 Mar 2020 [15:09]
Measured dimensions of fly for TC strike, conclude that the power dissipated is about 0.84W while the falling weight generates 4.8W
19 Mar 2020 [14:40]
ADJUST: +000ms/day to 15350 removed weights (magnets) from gravity arms, undoing 1580908800 . Amplitude should reduce.Was 48.44mrad, heading down to 47.8mrad
14 Mar 2020 [17:24]
reset last_drift
14 Mar 2020 [10:23]
top-up winding by James Penney and Alice Penney (matric '84)
13 Mar 2020 [19:06]
Winding by Jitka Stollova, Charles Roxburgh, Lisa Jardine-Wright, Willem H Ouwehand, Peter van Gool, Diduine van Gool
10 Mar 2020 [18:30]
restart of the weather station. It turned out that the back-up batteries were very old (best before date Jan07 ! Cleaning up the contacts and new batteries was all that was required.
06 Mar 2020 [22:14]
winding by Rui Li, Rosie Cates and Chloe Caron
01 Mar 2020 [15:00]
Restart of clocklogger after SD-card failure and reinstallaton. Instructions and software backup are here [link]
26 Feb 2020 [16:00]
SD-card failure on the RPi that runs clocklogger.
01 Mar 2020 [09:46]
correcting quarters at 9:15 (by Jessica Fintzen), they were out of sync by 15 minutes this morning
28 Feb 2020 [21:11]
winding by Areeg Emarah and Chloe1584181433 Caron
21 Feb 2020 [19:11]
winding by Areeg Emarah, Marika Cash, Afia Addai, Filsan Hassan and Chloe Caron
14 Feb 2020 [19:08]
winding by Tereza Constantinou, Jaz Shao and Chloe Caron
13 Feb 2020 [09:00]
There was a power interruption after which the weather station stopped working - not sure why.
08 Feb 2020 [14:06]
added more weight to the escapement arms.
07 Feb 2020 [21:10]
winding by Areeg Emarah and Chloe Caron
05 Feb 2020 [13:20]
added weights (magnets) to gravity arms to see effect of changing driving force, with Joel Williams and John Aldridge
02 Feb 2020 [17:34]
ADJUST: +250ms/day to 15350 with Shan Tan-Ya and Stefan Haselwimmer - after talking about
31 Jan 2020 [21:10]
winding by Areeg Emarah, Filip Wronowski, Aryaman Reddi and Chloe Caron
24 Jan 2020 [18:11]
winding by Bianca Zerbini (Shadowing scheme), Areeg Emarah and Chloe Caron
17 Jan 2020 [18:12]
winding by John Aldridge and Chloe Caron
14 Jan 2020 [23:03]
ADJUST: -500ms/day to 15100
10 Jan 2020 [13:18]
winding by Richard Hayward and Jessica Fintzen
09 Jan 2020 [17:47]
Calibrating the tilt sensors using a car jack with help from John Aldridge. The jack was lifting with a force of severall 100s of kg
03 Jan 2020 [16:16]
winding by Kazuo Newcombe
27 Dec 2019 [14:03]
winding with Luise Grosche, Scarlet Grosche, Malte Grosche, Wilke Grosche, Catherine Barnard, Anna Cary, John Cary, Sam Cary, Joe Cary.
20 Dec 2019 [13:59]
winding by Kazuo Newcombe
13 Dec 2019 [12:58]
winding by Richard Hayward and Jessica Fintzen
06 Dec 2019 [12:15]
winding by Ruadhai Dervan and Jessica Fintzen
29 Nov 2019 [19:34]
winding by David Levi, Areeg Emarah and Chloe Caron
22 Nov 2019 [19:09]
visit and winding with the Master Dame Sally Davies, for her 70th birthday, Willem Ouwehand, Natasha Broke, Philip Broke, Frances Pearce Gould, Rupert Pearce Gould and Marina Dekker-Thomson with Chloe Caron
18 Nov 2019 [08:26]
winding by Jierui Shi, Tom Durrant, Laszlo Mandoki, Adam Cavender, Peter (Heedo) Woo, Katelyn Chelberg, Emilie Pauwels, Andrew Gee
10 Nov 2019 [21:41]
checked that heater is running, and looked for any bits (cables etc) touching the pendulum. All looks OK. Also installed 4MB USB stick to pi-clock10
10 Nov 2019 [21:40]
ADJUST: -400ms/day to 15600
10 Nov 2019 [21:38]
Winding by Jeremy Zolnai-Lucas, Toby Proudfoot, Leo Gu, Jack Wade (from NZ), Andrew Gee and Chloe Caron
03 Nov 2019 [21:29]
top-up wind by Traian Dumitrica and Dan Bodansky with Jessica Fintzen
02 Nov 2019 [19:13]
winding by Tom McGachie, Areeg Emarah, Anya Gera, Filip Wronowski and Chloe Caron
31 Oct 2019 [11:45]
installed additional bubble tilt meter on the pendulum suspension, with John Aldridge.
26 Oct 2019 [23:38]
winding by John Summers with Kazuo Newcombe and John Aldridge for the time change
20 Oct 2019 [13:26]
winding by Kazuo Newcombe: +100ms/day to 16000
17 Oct 2019 [10:42]
power cycled GPS box and rebooted clock.t.c.a.u to try to resolve drift measurement glitches (jpsa)
13 Oct 2019 [21:16]
winding by Francois Vibert (Pembroke), Jemima Williams (Newnham), Mayeule Huard (Corpus Christi), David Abaev, Hugo Sonnery, Irene Svoronos and Chloe Caron (all French - zut alors!)
08 Oct 2019 [11:08]
on the day of the Installation of The Master Dame Sally Davies, honoured by visitors up the clock Philip Bonn and James Talbot.
07 Oct 2019 [14:04]
visit by Michael Bradley from CUED/EDC
06 Oct 2019 [20:13]
winding by Thomas Wilkins, Sean Liu, William Foster, Elizabeth Hanna, Filip Wronowski, Chloe Caron
04 Oct 2019 [12:56]
Visit by Douglas de Lacey from Girton. Peter in Perth will be very jealous!
29 Sep 2019 [16:41]
winding by Emilie Linfoot, Claire Linfoot McLean, Darin McLean, Mike Allison, Bob Grimshaw, Liz Grimshaw and Bridget Sarah Grimshaw, Rachel Sweet after TrinTalks
22 Sep 2019 [10:53]
winding by Ingo Fintzen, Sabine Fintzen and Jessica Fintzen
20 Sep 2019 [09:05]
visit by Osamu Furuya, Satoshi Fujita, Suzuko Tamashiro and Keisuke Minagawa from Tokyo Denki University
15 Sep 2019 [09:37]
winding by Kazuo Newcombe
08 Sep 2019 [10:23]
winding by Kazuo Newcombe
04 Sep 2019 [09:20]
correcting quarters (by Jessica Fintzen), they were out of sync by 15 minutes since yesterday
01 Sep 2019 [11:11]
winding by Ayse Polat, Ailsa Keating and Jessica Fintzen
27 Aug 2019 [11:59]
+0 ADJUST: +100ms/day to 16000 with Jessica Fintzen
26 Aug 2019 [16:27]
ADJUST: +600ms/day to 15900 with Tony Robinson
25 Aug 2019 [17:03]
Winding by Kazuo Newcombe. Also installed a BME680 Temp/Humid/Pressure/Airqual breakout board onto pi3
19 Aug 2019 [12:10]
Reposition temperature and humidity sensor into the belfry (hemh/jpsa) on pi 3
18 Aug 2019 [15:15]
Top-up wind with Chloe Caron - not uneventful! We moved the perspex case top cover which looks as if it was touching the pendulum. Also shifted the heater cable so that it's nowhere near the pendulum.
17 Aug 2019 [16:36]
ADJUST: -300ms/day to 15300
17 Aug 2019 [16:31]
top-up wind by Marcel Llavero-Pasquina. Also, fixed the going - the pendulum was touching the cable for the heater again.
16 Aug 2019 [10:27]
ADJUST: -300ms/day to 15600 - over three months since last regulation. Amazing. Regulation weight calibration is 104ms/day per gram. The set of eleven weights is approximately (in ms/day): 5=50mg 10=100mg 20=200mg 50=500mg 100=1g 200=2g 500=5g 1k=10g 2k=20g 5k=50g 10k=100g
11 Aug 2019 [10:43]
winding by Emily Marr, Gideon Gray and Kazuo Newcombe
04 Aug 2019 [23:37]
winding by Aryaman Reddi and Chloe Caron
28 Jul 2019 [16:09]
winding by Michal M Graczyk, Aryaman Reddi, Filip Wronowski, Areeg Emarah and Chloe Caron
21 Jul 2019 [13:38]
winding by Aaron Brick, David Garcia, Franziska Sielker, Cameron Brick, Iosifina Foskolou and Kazuo Newcombe
16 Jul 2019 [16:10]
visit by Agnes Lepicard, Vincent Chriqui et Alice Chriqui (3.5 mo !)
15 Jul 2019 [21:16]
last-drift fixed
15 Jul 2019 [13:31]
power turned off by TC electricians. Restart, last-drift mismatch
14 Jul 2019 [18:07]
winding with Aryaman Reddi, Filip Wronowski, Filsan Hassan, Areeg Emarah, Chloe Caron
08 Jul 2019 [19:08]
winding by Chloe Caron
03 Jul 2019 [10:19]
winding the quarters with Amelie, Maggie, Alice, Dexter, Eli, Archa, Malachi, Joann, Cedar, Mark, Andor, Rupert from Cambridge Steiner School
01 Jul 2019 [20:09]
winding by Aryaman Reddi and Chloe Caron
24 Jun 2019 [20:11]
winding by Ailsa Keating and Jessica Fintzen
17 Jun 2019 [19:26]
winding with Claudia R. Schneider, Muhammad Asadullah Javed, Gabriel Recchia, Ellen M. Jameson, and Jessica Fintzen
13 Jun 2019 [19:05]
noticed that the wire for the heater was touching the pendulum. This explains the curious racing of the last few days.
10 Jun 2019 [07:18]
winding by Kazuo Newcombe
05 Jun 2019 [21:05]
reconnected the pendulum chute heater - it seems to have become disconnected when the cavity thermometer tube was reposityed.
02 Jun 2019 [20:48]
winding with Kathy Talbot, James Talbot and Andy Harter
30 May 2019 [17:01]
winding with Charlotte Hester, Katie Kemplen, Catherine Munn and Robert Chris
23 May 2019 [08:05]
winding by Kazuo Newcombe
15 May 2019 [21:19]
winding by Clare Redfern, Stephanie Bryant, Geoff Cook, Rob Allin, Will & Rachel Simonson, Keith Fox, Colin Bell, Bob White, Farady Institute Termy Dinner, Climate Change with Katharine Hayhoe
12 May 2019 [08:03]
winding by Kazuo Newcombe and Christian Owen
04 May 2019 [21:12]
winding by Jessica Fintzen, Laura Glau, Bianca Patton and Chloe Caron
01 May 2019 [16:30]
ADJUST: +200ms/day to 15900 with Derek Leadbetter and Laurie Leadbetter
27 Apr 2019 [10:30]
reset last_drift - which is the place where clocklogger stores it's last-known value of drift because when clocklogger restarts it can't otherwise know just from the GPS pulse-per-second output how many seconds ahead or behind the clock is. Do this by stopping clocklogger, editting last_drift and restarting clocklogger, as follows: 1. open a Terminal window and type cd clocklogger/data which will change the directory to /home/pi/clocklogger/data 2. type: sudo systemctl stop clocklogger.service which will stop the clocklogger process 3. type: nano last_drift and edit the number there to something close to what you think the drift currently is, then ^x to exit and save 4. type: sudo systemctl start clocklogger.service which will restart the clocklogger process All done. This means that the left hand column here can be set to +0
27 Apr 2019 [10:18]
wind with Kazuo Newcombe and Chloe Caron.
27 Apr 2019 [09:35]
It seems the pendulum heater cable became discnnected about now
27 Apr 2019 [09:35]
restart with Kazuo Newcombe and Chloe Caron. Not sure why the clock stopped. Maybe the pendulum was touching something, eg the temperature probe tube?
21 Apr 2019 [20:12]
winding by Ingo Fintzen, Jessica Fintzen, Sabine Fintzen and Chloe Caron
16 Apr 2019 [18:50]
ADJUST: -300ms/day to 15700
14 Apr 2019 [20:10]
winding by Chloe Caron
07 Apr 2019 [09:36]
winding by Chloe Caron, corrected for Wednesday's pigeon event
04 Apr 2019 [11:48]
pigeon! stopped for 1 minute
31 Mar 2019 [00:22]
Summer Time - clock put forward one hour by Chloe Caron. Winding by Jonathan Dove, Davie Evans, Liesbeth Blom, Chloe Caron, Matthew Eve, Arturas Raudys, Alasdair Middleton, Susan Bolt, Ludvig Brekke, Rosa Rahimi Aminzavvar, Moamina BIlal, Areeg Emarah, Paul Bonaer, Santiago Cabrero, Pip Matthews, Nick Breeze, Gavin Stark,
26 Mar 2019 [11:04]
winding by Joey Isenberg, Steb Fisher and Chris Morley
22 Mar 2019 [08:07]
ADJUST: +500ms/day to 16000 by Kazuo Newcombe
22 Mar 2019 [08:06]
winding by Kazuo Newcombe
14 Mar 2019 [20:09]
winding by Aryaman Reddi and Chloe Caron
07 Mar 2019 [09:16]
winding by Natasha Wilson, Alexander Maund and Chloe Caron
06 Mar 2019 [14:41]
Fixed twist sunshade with self-tapping screw, which unfortunately sheared off in the hole, so will be a pain to remove. Aligned laser & tapped prism to centre spot on screen (which was actually why the twist readings have been broken recently - the sunshade was in fact not the problem this time). JPSA
27 Feb 2019 [22:20]
Top-up wind with Andrew Forrest, Nicola Forrest and Claudia Kuginis
24 Feb 2019 [17:23]
winding by Martine Colpaert and Peter Van Overschee from Leuven, with Rick Enns and Hilary Costello.
24 Feb 2019 [16:25]
ADJUST: -500ms/day to 15500
24 Feb 2019 [16:18]
looks like weights at a distance (N, towards St John's) improve twist, as can be seen now they're moved back. Looks better again.
24 Feb 2019 [16:13]
checked that heater is working - yes, it is hot. Closed gap on top of perspex box. Also, moved 6000 of weights closer to pendulum centre to see if twist could be fixed. Waiting ...
23 Feb 2019 [18:53]
ADJUST: -4000ms/day to 16000 by Chloe Caron
23 Feb 2019 [14:26]
This [link] seems to show that the driven scale factor for going vs amplitde is about -150 ms/day per mrad
23 Feb 2019 [13:20]
ADJUST: reset to 20000 - this will need further fine tuning later once the amplitude settles. [link]
23 Feb 2019 [11:40]
In doing all this the Wyler orange level was disconnected, removed and replaced. Also the mirror for the twist measurement had to be repositioned.
23 Feb 2019 [11:40]
4. removed large metal frame from barometric compensator. Now both aneroid stacks move independently. It will be good to see if the compensator performance is improved.
23 Feb 2019 [11:40]
3. lifted pendulum and replaced suspension with the original. Joined by Chloe Caron and Kazuo Newcombe for this - very good to have help! The original suspension is defiitely not square, but the pendulum is now ticking much more evenly.
23 Feb 2019 [11:40]
2. reconnected heater and made more robust connection so that it won't come unplugged again ... hopefully!
23 Feb 2019 [11:40]
1. removed fan and tube - it;s ugly and not really very effective
23 Feb 2019 [11:39]
Clock restart, but with a few things done with the opportunity given that the clock has stopped:
23 Feb 2019 [07:04]
Clock stopped. Not exactly sure why, but the evidence suggests that the heater fell down and onto the bob causing the pendulum to hit the IR sensor as evidenced by large twist and the pendulum amplitude dropping rapidly. [link] . Here [link] it's clear that the heater had fallen down.
22 Feb 2019 [10:12]
Visit by John Schellnhuber, Patricia Mirrlees, Matthew Agarwala, Lukas Gast, Marcel Weiss and Parwana Fayyaz
22 Feb 2019 [10:11]
ADJUST: -500ms/day to 49050
19 Feb 2019 [13:19]
correct quarters - out of sync by 15 mins... and a top-up wind of five turns
19 Feb 2019 [12:01]
GCR=47.0 on top layer
18 Feb 2019 [19:15]
winding by John Aldridge
17 Feb 2019 [20:02]
ADJUST: +1000ms/day to 49550
17 Feb 2019 [20:01]
Visit by David Anderson - from Umbria ex Hong Kong, Bramhall Lane South, London, Dundee and Farnham ...
16 Feb 2019 [12:16]
Visit by Dan Bodansky from The Valley of the Sun! And we reconnected the heater wires that got loose last eek, thanks to JPSA
11 Feb 2019 [08:09]
ADJUST: +500ms/day to 48550
11 Feb 2019 [08:09]
winding by Ben Yass and Chloe Caron
03 Feb 2019 [21:09]
winding by Chloe Caron
02 Feb 2019 [18:53]
reset twist sensor sunshade again (jpsa)
27 Jan 2019 [12:13]
winding by Claire Murray, Pip Matthews, Lou Strasser, Mike Strasser
25 Jan 2019 [08:10]
winding by Ben Yass and Chloe Caron
17 Jan 2019 [19:14]
ADJUST: -750ms/day to 48050
17 Jan 2019 [19:13]
winding by Chloe Caron
10 Jan 2019 [08:38]
top-up wind
10 Jan 2019 [08:05]
Wyler level repositioned (and araldited onto its magnetic feet), clock reset by advancing 10 hours. Noticed that wind from the hour strike fly causes the barocomp to wobble a lot...
09 Jan 2019 [21:45]
the orange Wyler level fell off it's perch and stopped the clock!
07 Jan 2019 [21:07]
winding by Kazuo Newcombe
07 Jan 2019 [21:00]
switched off the fan - leaving the 8.1W heater running.
04 Jan 2019 [11:03]
added a 10ohm resistor, driver by 9V to provide 8.1W of heating. Let's see what happens!
03 Jan 2019 [10:33]
reversed the fan from blowing cold air down to sucking warm air up - with Kazuo Newcombe
31 Dec 2018 [16:20]
moved thermocouple from near the escapement to inside the perspex box, just by the fan intake. Knocked the pendulum hence restart.
31 Dec 2018 [16:17]
top-up wind by Elizabeth Wallfisch - sister extraordinaire!
30 Dec 2018 [15:39]
ADJUST: -15000ms/day to 48800
30 Dec 2018 [15:27]
messing about a bit this afternoon. Replaced the fan (see below, 26 March 2013) which was fiddly - had to stop the pendulum to position the 35mm plastic hose down to the bottom of the pendulum chamber without interfering with the swing of the pendulum. The pendulum got a few knocks so the going is starting from scratch. I added a couple of 100g lead weights, worth about 10000ms/day each, and I removed 15000ms/day of brass weights. Note the fan is blowing cool air down to the bottom (which I think is what it must have been doing back in 2013). But now we have a perspex case at the top and a good seet of thermometers.
29 Dec 2018 [12:06]
repositioned the orange Wyler level - it had fallen off it's magnetic supports - again! I glued the magnets on more carefully - with balsa cement. In doing so Iknocked the E-W vial which I re-leveled, repositioned and rotated. It too seems to be migrating. The other two vials seem to be OK on level, but rotating. I re-oriented them all and put some balsa cement on each of the vials.
29 Dec 2018 [12:05]
29 Dec 2018 [12:00]
GCR=50.01s on lower layer
22 Dec 2018 [12:33]
winding with Laura Oosterbeek, Reece Oosterbeek and Kazuo Newcombe
22 Dec 2018 [12:32]
ADJUST: -300ms/day to 63800
15 Dec 2018 [13:19]
Winding by Victoria Royce, Leonard Royce, Kazuo Newcombe and John Aldridge (also repositioned Wyler level because it was creeping again)
10 Dec 2018 [14:43]
Top up wind by jpsa
08 Dec 2018 [12:00]
ADJUST: +600ms/day to 6410015460848001546084800
08 Dec 2018 [11:58]
winding by Danielle Barr, Guido Ruijl, Fabian Gomperts Willis, Sarah Nelson, Miranda Gomperts, Kazuo Newcombe and John Aldridge
05 Dec 2018 [23:00]
reset pi-clock5 spirit level position after camera remounting on 30th Nov (jpsa)
01 Dec 2018 [10:07]
changed last_drift from 7.5345 to 1.5 . clocklogger stoped with sudo systemctl stop clocklogger.service and restarted with sudo systemctl start clocklogger.service
30 Nov 2018 [23:26]
top-up wind after the Audit Feast: Charlotte Rossetti, Didier Queloz, Catherine Aiken, Brian Woods, Matthew Juniper, Joe Smith, Stephen Layton, Kirsty Ross, Rob Miller Ian McFarland
30 Nov 2018 [17:31]
finished fiddling. Thanks to Kazuo Newcombe, Jakub Suchanek and John Aldridge.
30 Nov 2018 [17:15]
ADJUST: +30000 to 63500 (large change due to n1546084800ew adjustment platform)
30 Nov 2018 [16:30]
. pendulum disturbance
30 Nov 2018 [16:30]
. pendulum disturbance
30 Nov 2018 [16:30]
. pendulum disturbance
30 Nov 2018 [16:30]
. pendulum disturbance
30 Nov 2018 [16:30]
. pendulum disturbance
30 Nov 2018 [16:29]
. pendulum disturbance
30 Nov 2018 [16:29]
. pendulum disturbance
30 Nov 2018 [14:33]
starting a few new things: 1. refit regulation platform to enable twist regulation. 2. New spirit-level vials for measuring vee-block tilt (N-S and E-W) and N-S suspension tilt. 3. New Raspberry pi-clock9 with camera and illuminator to monitor the three new spirit levels. 4. New screws on pi-clock5 camera.
28 Nov 2018 [23:24]
winding by Johan Bolhuis, Garath Wynn-Williams matric 1963, Julia, [Alun Preece, Lloyd Lloyd, Charles Garraway, Nigel Grant Rogers, Rodney Holder - matric 1968 - a 50-year reunion]
24 Nov 2018 [12:52]
fixed the pigeon event by running the clock forwards by 18 seconds. A few knocks of the pendulum while moving the level and trying to fit glass vial spirit levels. Note the change in twist, must be due to shifting the stiction of the vee block. Also, opened the perspex pendulum case to see if it changes air flow and temperatures.
23 Nov 2018 [20:12]
ADJUST: -500ms/day to 33500
23 Nov 2018 [20:12]
winding by Chloe Caron
21 Nov 2018 [10:44]
Pigeon event - clock stopped by about 18 seconds (thanks to Chloe Caron for spotting this)
17 Nov 2018 [20:10]
ADJUST: +500ms/day to 34000
17 Nov 2018 [20:10]
winding by Ben Yass and Chloe Caron
10 Nov 2018 [09:07]
winding by Part IA Engineers: Clara-Ann Cheng, Jakub Suchanek, Eoin Walsh, Hai Vu Quach, Sam Ernest, Lu Chen, Xinyang LI, Kazuo Newcombe, Ming Yang, Jonathan Edwards and Andrew Gee
10 Nov 2018 [08:40]
ADJUST: +500ms/day to 33500
08 Nov 2018 [19:30]
reposition the twist sensor sunshade which had slipped and was blocking the laser light path. I think that probably accounts for all the unusual twist readings since about 6am on 7th November (jpsa)
02 Nov 2018 [20:13]
winding by Danny Smith, Anna Mills, Kadi Sun, Aditya Jain, Robert Ogilvy, Chloe Caron and Andrew Gee
27 Oct 2018 [23:02]
Clocks go back. Pendulum stopped with Emily Winslow, Gavin Stark and John Aldridge. We removed the pendulum suspension (using a neat pendulum lifter) and put in a more symmetric suspension. Doesn't work so well!
26 Oct 2018 [08:11]
more filming with Chloe Caron, Rui Li and Graham Newman
26 Oct 2018 [08:03]
winding by Chloe Caron and Rui Li
24 Oct 2018 [10:43]
filming with Sue Dougan for a BBC Radio Cambs piece on the hour change. Stopped the clock for a bit, and removed the extra weights from the barometric compensator.
23 Oct 2018 [08:17]
ADJUST: +400ms/day to 33400
23 Oct 2018 [08:14]
winding by Suhaa Mahmood and Chloe Caron
20 Oct 2018 [16:30]
rebooted pi-clock5 because it had hung, not sure why (jpsa)
15 Oct 2018 [20:08]
ADJUST: -500ms/day to 33000
15 Oct 2018 [20:00]
winding by Ben Yass and Chloe Caron1546084800
08 Oct 2018 [08:12]
winding by Thomas Morrison, Mariana Gee Olmedilla, Andrew Gee and Chloe Caron
02 Oct 2018 [14:10]
today the carpenters fitted a nice perspex box around the pendulum - hoping we'll see a more-uniform temperature up the pendulum so that temp compensation will be improved. Pendulum got knocked a few times as we measured stuff and generally hacked about.
01 Oct 2018 [14:10]
removed the extension regulation arm which weighs 3000g. ADJUST: +31100 ms/day to 33500
30 Sep 2018 [20:31]
winding by Neil Brewis, Emma Brewis, Emma Gee Olmedilla, Andrew Gee, Chloe Caron with John Aldridge.
25 Sep 2018 [09:55]
ADJUST: 250 ms/day to 2400. Why did the -250 adjustment on the w/e have such a big effect?
25 Sep 2018 [10:00]
removed the pendulum hood.
23 Sep 2018 [11:16]
ADJUST: -250 ms/day to 2150
23 Sep 2018 [11:15]
winding by Khan Baykaner and Asal Faraghat with Hilary Costello.
16 Sep 2018 [17:24]
winding by Ashleigh Bridges and Mark Irving with John Aldridge
16 Sep 2018 [10:29]
partial winding with Andy Skipwith and John Robinson - MET graduates, matric 1989!
09 Sep 2018 [14:02]
Winding by Barbara Hassall, Martin Cassell, Neil Taylor, Angela Taylor with John Aldridge
02 Sep 2018 [13:47]
ADJUST: +300 ms/day to 2400 - it looks as if forecast for high pressure will not let the clock catch up
02 Sep 2018 [11:22]
winding by Issam Kourbaj
02 Sep 2018 [11:21]
ADJUST: +300 ms/day to 2100
02 Sep 2018 [11:01]
GCR 49.0s on low layer, pleasant day
26 Aug 2018 [12:04]
winding by Ben Yass and Chloe Caron
19 Aug 2018 [12:03]
winding by Ben Yass and Chloe Caron
12 Aug 2018 [12:02]
winding by Rob Elder with Pip Matthews.
05 Aug 2018 [11:17]
winding by John Aldridge GCR=48.5s on upper layer, hot day
30 Jul 2018 [11:06]
visit with David Hunt of Willingham who restored Beyer Square Piano #864 of 1788. Is David related?!!
29 Jul 2018 [11:05]
winding by Rick Lupton, Florence Lupton, Hugh Lupton, Claire Isbester, Noel Privett, Sue Washington
28 Jul 2018 [19:40]
bell not sounding, fixed with help of Freddie Blake, Benjamin Blake,Leticia Blake, Chris Blake, Tanya Codd, Ted Codd and Cathy Ennis
24 Jul 2018 [22:08]
A quick Byrd 3-part up the tower with Alex Jenkin, Sophie Sanford, Jonny Tsang and John Aldridge
22 Jul 2018 [11:24]
ADJUST: -300 ms/day to 1800
22 Jul 2018 [11:05]
winding by Rupert Gatti and company, Aryaman Reddi, Chloe Caron
21 Jul 2018 [09:50]
fixed hood touching pendulum problem. Indeed, tape was unstuck. Now amplitude rises and going is restored to normal.
20 Jul 2018 [01:00]
it appears the hood has moved (I guess some tape has become unstuck) and is touching the pendulum. Amplitude had dropped and going has risen.
15 Jul 2018 [11:22]
winding with Pamela Krones, Nancy Emig, Torsten Emig, Ted von Hippel, Filip Wronowski, James McBride, Areeg Emarah, Chloe Caron
12 Jul 2018 [13:00]
fittedf a hood on pendulum to help keep temperature constant along length of pendulum.
07 Jul 2018 [22:20]
winding with Carla Troyas Martinez, Leyre Troyas Martinez, Rita Troyas Martinez, Amelia Sloan, Jackie Getson, Peter Sloan, Lettie Thomas, Robert Elder, Beatrice Hunt, Pip Matthews and John Aldridge
30 Jun 2018 [14:28]
ADJUST: -200ms/day to 2100
30 Jun 2018 [14:25]
Winding with Ted von Hippel and Andrew Lockley
26 Jun 2018 [16:48]
Winding with John Aldridge, Tom Mullock
26 Jun 2018 [16:43]
ADJUST: +300ms/day to 2300
19 Jun 2018 [23:18]
Fairhaven murder mystery tour: Joanna Page, Robyn Sorensen, Eleanor Cramer, Pip Matthews, Paul Ashley, John Aldridge ...
12 Jun 2018 [18:05]
Choir winding: Tilly Dichmont, Frankie Postles, Ellie Tobin, Susie Hill, Anita Monserrat, Christopher Moore, Asher Oliver, Alex Hamilton, Lucy Prendergast
10 Jun 2018 [10:51]
ADJUST: -250ms/day to 2000 1546084800
05 Jun 2018 [08:01]
winding by Eve Avdoulos, John Anderson, Spencer J Brennan, Christoph Kehle random assortment of hockey players
28 May 2018 [20:05]
winding by Imogen Richards and Chloe Caronilip
21 May 2018 [08:01]
ADJUST: -250ms/day to 2250 and top-up wind
17 May 2018 [08:50]
winding with Fiona Holland and Shaun Peel (BBC East)
13 May 2018 [00:06]
winding by Ben Yass and Chloe Caron
06 May 2018 [18:05]
ADJUST: +500ms/day to 2500
05 May 2018 [11:09]
winding by Ben Yass and Chloe Caron
27 Apr 2018 [23:16]
winding just in time ... by Ian Whitwam - many thanks!
20 Apr 2018 [11:22]
winding with Mahee Walter. Mathieu Walter, Maite Votocek, Antoine Walter visiting from Paris and Francoise Votocek, Paul Ashley, Chloe Caron, John Aldridge, Graham Newman
16 Apr 2018 [17:12]
winding by Dana English, Rui Li, Yae Chan Yang, Olga Zadvorna, Guangda Yang, Ryan Lin, Paul Coxon, Ben Moss, Chloe Caron
15 Apr 2018 [11:25]
repositioned sunshine sensor, installed new painted laser screen, restarted sunshine/bubble pi because it had locked up (dunno why), inadvertently knocked wyler level
09 Apr 2018 [12:30]
installed new RPi with experimental sunshine sensor, and a camera looking at a bubble-level on the brickwork to try to see whether the tower as a whole is tilting (jpsa)
09 Apr 2018 [09:09]
winding by Areeg Emarah and Chloe Caron. Bravely waited until after 10am confident that the strike would last the full 7 days 12 hours, thanks to the adjustment of 27 January.
01 Apr 2018 [21:28]
wind with Andrew Lockley - who gets muddled between Oxford and Cambridge - mein Gott!
29 Mar 2018 [14:02]
top-up wind (8 turns = approx 24 hours) with Guillermo Aguirre Esponda - here from Mexico City with permission from his daughter, remembering our mutual friend and mentor Ken Wallace
26 Mar 2018 [16:00]
a few tweaks, with John Aldridge: 1. stop pendulum to lower the prism by a couple of mm to make sure that the twist laser clears the clock-bed beam; 2. cleaned the prism (a fingerprint was causing a big diagonal difraction streak); 3. replace the laser screen with a 1mm polythene sheet; 4. calibrated the tilt level (found that it was pretty good, 1mV/mrad and that the zero-offset knob doesn't introduce scaling errors); 5. restart pendulum and check going, no regulation required.
25 Mar 2018 [00:20]
ADJUST: -22000ms/day to 2000 as a result of all the meddling. restart the clock
24 Mar 2018 [23:00]
various things done on this summer-time-change night with James Strachan, John Aldridge, Robert Spencer, Graham Newman : 1. replace barometric compensator with a magnetic weight platform to allow for twist adjustment; 2. change orientation of the twist laser prism so that the direct-reflection 'flying spots' are on-screen for all theta; 3. Install a wide (aluminium) regulation bar so that regulation weights can be positioned off-centre; 4. installed four graphite-impregnated 1mm-thick nylon pads into the vee-block to reduce friction on pendulum tilt. This meant that the IR sensor neded to be shifted upwards a short distance so that it runs true.
24 Mar 2018 [19:00]
pendulum free decay experiment, lifted escapement and allowed pendulum to swing freely until 11pm, with John Aldridge and Robert Spencer
24 Mar 2018 [13:00]
induced twist by moving all the regulation weights to a distance of about 200mm from the pendulum centre (put them pack on centre for the 7pm free-decay experiment)
18 Mar 2018 [12:20]
ADJUST: +700ms/day to 24000 in readiness for clock change next weekend
18 Mar 2018 [12:05]
winding by Cambridge Blue and Green Badge Guides: Deborah Vaudin, Fran De'Ath, Tim Pearce Higgins, Ruth Meyer and Helen Barrs
16 Mar 2018 [16:17]
Adjusted twist laser brightness. Not sure whether the rheostat had got knocked, or whether the moving of the prism had affected it, but the camera was underexposing, resulting in noisy measurements. (jpsa)
16 Mar 2018 [12:51]
visit by Nancy Hynes and Oliver Morton
12 Mar 2018 [17:32]
rotated the tilt meter by 180 degrees
11 Mar 2018 [19:01]
forgot to wind the clock earlier. Rap on knuckles. Wound and reset for 7pm.
11 Mar 2018 [19:01]
I got it all fixed in about 15 minutes: The clock had stopped at 5.44pm and it was restarted at 6.50pm so I had to advance the quarters by one notch. The Trinity Strike had stopped during the strike of two, so that needed advancing 5 notches. Fortunately the St John's strike was still in synch with the Trinity Strike. The clock had to be advanced by 1h6m, with all bells on silent. Then did a full wind
09 Mar 2018 [12:43]
ADJUST: +300ms/day to 23300 fine tuning1546084800
09 Mar 2018 [12:35]
advance by 80 seconds - forgot to do that last night
09 Mar 2018 [00:20]
ADJUST: +1000ms/day to 23000 after raising the laser prism up the pendulum shaft - this was to introduce up-down asymmetry in order to determine the sign of the twist measurement.
04 Mar 2018 [00:37]
ADJUST: -1400ms/day to 22000 fine tuning
04 Mar 2018 [00:34]
remove USB level (disturbed orange level)
04 Mar 2018 [00:31]
ADJUST: -5000ms/day to 23400 on account of removing the barocompensator
04 Mar 2018 [00:26]
release jack, observe further twist and tilt change
04 Mar 2018 [00:21]
jack up central beam to 200kg, observe further twist and tilt change
04 Mar 2018 [00:15]
jack up central beam by 100kg, observe twist and tilt change
04 Mar 2018 [00:00]
restart twist loggerilip
03 Mar 2018 [23:46]
repeat twist experiment then restart pendulum
03 Mar 2018 [23:45]
installed new solid-state tilt sensor in parallel with the existing orange level
03 Mar 2018 [23:07]
stop pendulum, remove barometric compensator, replace twist prism, replace yellow-painted glass on laser screen with ground glass panel
03 Mar 2018 [23:05]
torsional disturbance to measure twist natural frequency while swinging and at rest
03 Mar 2018 [23:00]
arrived with Pip Mathews and John Aldridge for winding and to do some experiments. Removed heater from clock case. Put a curtain up in the window to block sunlight.
03 Mar 2018 [17:00]
put fan heater in clock case
28 Feb 2018 [10:03]
visit by Tom Besinger from Hainfeld and Frank Besinger from Berlin - just like old times!
28 Feb 2018 [08:48]
install new twist monitoring code, correct (at display time) erroneous pix->mrad scale factor used since 16-Jan (jpsa)
26 Feb 2018 [09:30]
with Stefan Savage, measuring some dimensions on the pendulum for some mods to be fitted on 24 March (clock change night). Switched off the level for a bit, and knocked the pendulum about accidentally.
24 Feb 2018 [15:01]
winding by Caitlyn Rayney and Charlie Vaughan - Perth and Melbourne respectively.
17 Feb 2018 [12:15]
replaced vellum screen on the laser twist sensor with a white polythene film. Thanks to John Aldridge for his help.
17 Feb 2018 [10:35]
noticed that two 200ms/day weights had fallen off the regulation platform. They were reinstated.
17 Feb 2018 [10:07]
Winding by Kelly Wing, Chloe Caron, Robert Spencer
13 Feb 2018 [13:15]
advance the clock by 50 seconds with Kristina Bifani
13 Feb 2018 [13:45]
Oh no! Pigeon event. The clock stopped for 50 seconds. Is the pigeon wire not working?
09 Feb 2018 [22:28]
winding with Rupert Thornely-Taylor and Emmanuel Dormyilip
06 Feb 2018 [13:04]
experiment, engaging the maintaining weight to see what effect it has on amplitude. Note that amplitude drops by about 0.09mrad.
06 Feb 2018 [09:16]
winding by Cameron Brick, David Brick, Mary Male, Kirsty Ross (and bump, again!), Adam Reeves Areeg Emarah
02 Feb 2018 [14:30]
ADJUST: -500ms/day to 28400
29 Jan 2018 [21:25]
winding by Roy Brander, Connie Brander and Smita Hope Gopisetty with Hilary Costello explaining the various temperature compensation, pressure compensation and general working of the clock - an enthusiastic and interested bunch
29 Jan 2018 [14:41]
ADJUST: +200ms/day to 28900 with Nick Breeze
29 Jan 2018 [14:40]
rotated the tilt sensor. It should now be giving readings arond +800mrads and the slope of plots vs tilt will be opposite sign
29 Jan 2018 [14:38]
shifted all 28900 to distance 200mm from pendulum centre
27 Jan 2018 [14:02]
shifted 23700 of the weights on theGCR regulation to from 50mm to 150mm off-centre as an experiment to see if pendulum twist can be controlled.
27 Jan 2018 [12:25]
ADJUST: -5000ms/day to 28700 owing to the added mass of the regulation platform.
27 Jan 2018 [12:05]
clock restarted
27 Jan 2018 [11:50]
cavity probe reinstalled in cavity
27 Jan 2018 [10:14]
cavity probe removed and insulation spacers added. Laid down on the carpeted floor to check for zero offset. Note that by 11.45am the temperatures have settled down to the same value.
27 Jan 2018 [09:45]
pendulum stopped for access to pendulum case, plugging holes to get rid of draught. Also removed nut on Trinity Strike weight to give two dongs of extra time, hoping to get 7 days 12 hours between winds. Also fitted temporary platform to allow regulation weights to be placed up to 150mm off-centre as a means of regulating twist.
27 Jan 2018 [09:41]
09:41.50 close doo1546084800r to roof, End of experiment
27 Jan 2018 [09:39]
09:39:10 open door to roof,
27 Jan 2018 [09:37]
09:37.50 open clock case and remove shuttering around pendulum,
27 Jan 2018 [09:36]
09:36:10 open door to C5,
27 Jan 2018 [09:34]
09:34:30 close door to C5,
27 Jan 2018 [09:32]
09:32:15 pendulum case opened,
27 Jan 2018 [09:29]
09:29:15 hot water turned off,
27 Jan 2018 [09:28]
09:28:30 run hot water,
27 Jan 2018 [09:26]
09:26:50 close window,
27 Jan 2018 [09:25]
09:25:00 open window of C5,
27 Jan 2018 [09:22]
09:22:00 enter room C5 (Dr Hopkinson),
27 Jan 2018 [09:16]
Experiment to understand Bedmaker Effect: 09:16 enter clock room,
26 Jan 2018 [17:35]
end of experiment. [link] I reckon the shift of weight was about 0.25kg by 40mm - that's the same as 100kg by 0.1mm The pendulum bob is 100kg and the length is about 2m so the apparent tilt change is about 0.05mrad Look at x-y plot here of twist vs tilt (nb tilt volts is 1mrad/volt). [link] So it looks as if the 0.05mrad is in the right ballpark.
26 Jan 2018 [15:00]
experiment to see if shifting 20000ms worth of regulation weights makes any difference to twist. Looks promising
25 Jan 2018 [21:28]
winding by Robert Spencer, Khalid Aleen and Chloe Caron
25 Jan 2018 [21:27]
ADJUST: +1400ms/day to 33700
24 Jan 2018 [10:46]
improve chamber te1546084800mperature logging: correct bottom-top order, log at hh:mm:00 times, log to full 1/16 C precision (jpsa)
23 Jan 2018 [18:00]
checked the pendulum chamber thermometers, cleaned out the muck at the bottom, accidentally knocked the pendulum. As a test, left pendulum case door open.
18 Jan 2018 [09:14]
winding by Chapel eventers, Eesha Khare, Frances Ding, Zhe Li, Cheryl Jaing, Peter Juhasz, Kirsty Ross (+Bump - big), Gui Fritas, Tobias Tan, Paul Johnson, Vijesh Bhute, Aga Machaj, Thomas Graf, Janko Ondras, Elizabeth Huang, Charlotte Keinhorst, Peggy Xu
16 Jan 2018 [09:14]
ADJUST: +200ms/day to 32300 with Chloe Caron
15 Jan 2018 [18:56]
ADJUST: -250ms/day to 32100 on account of lowering the prism slightly
15 Jan 2018 [18:10]
reinstalled the laser twist sensor and RPi. Much neater casing and wiring.
11 Jan 2018 [12:11]
ADJUST: -150ms/day to 32350
11 Jan 2018 [12:10]
winding with Harry Druiff and Len Howlett
06 Jan 2018 [23:06]
ADJUST: +300ms/day to 32500 fine tuning after raising the prism. Also refitting the laser spot light shield that had fallen off.
06 Jan 2018 [23:05]
winding with Eloise Hunt, Helen Hayward, Richard Hayward, Patrick Maxwell, Ed Maxwell, Wilke Grosche, Malte Grosche, Michael Watt, Alan Windle after the Twelfth Night Feast
01 Jan 2018 [21:28]
Debounced the edge detection for the pendulum & PPS sensors (jpsa)
30 Dec 2017 [23:20]
ADJUST: +1015ms/day to 32200 to account for the raising of the prism on the pendulum - and a top-up wind
30 Dec 2017 [22:02]
winding with Mark Irving and John Aldridge.
30 Dec 2017 [20:32]
Replaced twist laser unit with a sleeker version, and stopped pndulum to raise the prism into line with the new laser - does it work?
23 Dec 2017 [13:05]
winding with John Aldridge
18 Dec 2017 [17:40]
winding, and switch to Raspberry Pi with Rick Lupton and John Aldridge
11 Dec 2017 [20:50]
winding by Sander v1546084800an der Linden, David Spiegelhalter, Anne Marthe van der Bles, Alex Freeman, Zsofia Szlamka, George Farmer, George Michael Pearson, Cameron Brick, Leila Finikarides
10 Dec 2017 [19:06]
clocklogger PC needed a "sudo reboot" and then "fsck /dev/sda1" (file system consistency check) which found many disk errors which were fixed.
04 Dec 2017 [09:14]
winding by Natalie Jones, Stephen Bayley, Annalise Higgins and Konrad Viebahn
26 Nov 2017 [21:15]
winding by Chloe Caron, William Baldwin, Ben Yass, Areeg Emarahilip
19 Nov 2017 [10:13]
winding by Chloe Caron, William Baldwin, Ben Yass
11 Nov 2017 [23:30]
ADJUST: +35ms/day to 31185 - by Chloe ... who is happy to take the blame.
11 Nov 2017 [23:20]
winding by Chloe Caron, Wang Yi, Chen Zhihang, Ben Yass, Wilfred Salmon, William Baldwin,
04 Nov 2017 [12:41]
ADJUST: -100ms/day to 31150
04 Nov 2017 [12:39]
winding by: William Baldwin, Rachel Onions, Phil Tower, Junhyuk Hwang, Philippa Nunn, Ben Yass, Max Vigdorchik, Haopeng Zhou, Chloe Caron,
29 Oct 2017 [01:22]
ADJUST: -50ms/day to 31250
29 Oct 2017 [00:11]
winding and time change by Ben Yass, Chloe Marie Leila Caron, Philippa Nunn, Rick Enns, Hilary Costello, John Aldridge, Chris Nickolaus, Alice McMichael, Andrew Gee
23 Oct 2017 [20:22]
winding by Carla Troyas Martinez, Sara Troyas Martinez, Giulio Crisanti, Adrian del Ser and Edward 1546084800Karmazyn
16 Oct 2017 [08:37]
winding by Anisiya Parker, Ulyana Gumeniuk-Parker (past Fellow Commoner in Creative Arts) and Iain Parker
08 Oct 2017 [21:25]
winding by Eriks Esenvalds, Stephen 'sid' Layton, Paul Ashley - after evensong with Howells Cool. Reg
01 Oct 2017 [11:28]
winders from Christ's - (and a ring-in from Caius) Miriam Guth, Fin Brown, Emily Marr, Dom Yates, Vilda Markeviciute, Binbin Jin and Emily Morgan (the ring-in)
01 Oct 2017 [11:28]
ADJUST: +150ms/day to 31300
23 Sep 2017 [23:09]
winding after Erasmus Concert: Rose Bradshaw, Ellen Jameson, Dan Tidhar, Mary Earl, Michelle Rigozzi, Ian de Massini, Imogen Phillips, Chris White, Lucy Wilson, Edward Lilley, Johanna J. S. Finnemann, Patrick Welche, David Lavender, Alexander Blustin
16 Sep 2017 [16:09]
09 Sep 2017 [13:46]
ADJUST: -100ms/day to 31150
09 Sep 2017 [13:40]
top-up wind by Richard Thomas, Joanna Pyman, Philippa Mann and Francesca Mann
07 Sep 2017 [20:14]
winding by Mark Burrell, Reece Oosterbeek and Laura Oosterbeek - a flock of Kiwis
31 Aug 2017 [14:08]
top-up wind by Jachin Chng Yee, marissa chng min, Chng Ying Elizabeth, Sarah Siah, Chng Kai Fong (matric '97) - visiting from Singapore
30 Aug 2017 [12:05]
top-up wind by Hilary Dennis, Oliver Dennis, Rosanne Hunt
29 Aug 2017 [17:05]
winding by membrers of the Trinity PostDoctoral Society
22 Aug 2017 [17:05]
winding by Philippa Matthews
15 Aug 2017 [17:05]
winding by Rick Lupton and Chris Nickolaus
08 Aug 2017 [11:43]
ADJUST: +200ms/day to 31250
08 Aug 2017 [11:35]
winding with TC PostDoc Society: Ruben Valbuena, Manon Kok, Sara Lopez-Gomollon,Jeongmin Choi, Francisco J Navarro, David Llewellyn-Jones, Gareth Richards and new Title-A Fellows George Roberts and Hannah Stern
01 Aug 2017 [17:05]
winding with Chris Nickolaus and friend
25 Jul 2017 [17:05]
winding by Rick Lupton and some of his research group
20 Jul 2017 [09:00]
visit with Kasia Ladds from Cambridge Enterprise, experiment to determine torsional period of pendulum: 10 cycles in 16.1sec so T = 1.61s
19 Jul 2017 [12:09]
ADJUST: -150ms/day to 31050 with John Aldridge helping to calibrate the tilt sensor
18 Jul 2017 [18:34]
winding with guests of the Cambridge Summer Music festival
11 Jul 2017 [08:13]
top-up wind, more experimentsGCR
10 Jul 2017 [11:15]
top-up wind, and experiments on twist vs angle
08 Jul 2017 [22:42]
winding by Jitka Stollova, Lynnea Shuck, Eleanor Cramer, Pip Matthews and Alice McMichael - after the Fairhaven Summer Concert
01 Jul 2017 [11:15]
top-up wind by Tony Howes, Catherine Howes, Oliver Howes, Max Howes amd Mimi - a flying vsit from Brisbane. Also Jonnie Hunt, Ellie Hunt and Alex Hunt
30 Jun 2017 [17:13]
winding by the committee of the Trinity Postdoctoral Society - Samantha Hajna, Simon Hoer, Barbara Herdy & Adina Feldman, President emerita of the Postdocs of Cambridge Society (PdOC)
23 Jun 2017 [08:10]
winding by Mechanics Lab technicians Tom Guilbride, Simon Marshall,Graham Smith, and Curator of the Whipple Museum of the History of Science Joshua Nall and also co-scouting parents Naomi Griffiths and Jonathan Spikey Griffiths
15 Jun 2017 [20:13]
wind for Rag: Hans Yu, Nicholas Jamieson, Maxim Kuvshinov, Jenna Foale, David Ren, Jose G. Aguilar, Petr Kungurtsev, Jocelino Rodrigues, Nguyen Anh Khoa Doan, Francesca De Domenico and Denis Busquet
14 Jun 2017 [12:00]
GCR=49.1s on lower layer,
06 Jun 2017 [17:50]
wind by Ryan Mulholland and Chris Nickolaus
01 Jun 2017 [15:15]
ADJUST: -150ms/day to 31200
31 May 2017 [20:28]
winding by Greg Winter, Andy Lim (matric '76), Hwee Hua Lim (matric G '78), Jane Corbett (matric '78), Lydia Heinrichs, Hans Yu
24 May 2017 [17:43]
Wenwen Li, Bingan Chen, Julia Clarke, Richard Clarke, David Boulton, Immanuel Kemp - winders from Arthur D Little, on a glorious sunny day
22 May 2017 [21:03]
ADJUST: -150ms/day to 31350 fine tuning
22 May 2017 [15:46]
rotating the prism - it wasn't quite straight
22 May 2017 [15:25]
ADJUST: -16800ms/day to 31500 on account of the added mass of the prism
22 May 2017 [15:24]
witnesses to fitting a prism and laser to the pendulum: Orlando Pope, James Pope, Margaret Pope, Eleanor Pope, Kenneth Pope, Anna Pope - believe it or not all related - and from AUCS Adelaide. Also Andrew Lantry from Worshipful Company of Clockmakers and Baba Soile MEng (almost!) We also refitted the temperature probe
19 May 2017 [22:01]
winding after a SPRNGG meeting with Renaud de Richter de Montpelier et Philip Davies de Birmingham!
15 May 2017 [10:15]
stopped pendulum to remove temperature probe from pendulum shaft - temperature sensors need to be cross-calibrated
13 May 2017 [09:20]
winding by Joe Sherwood - IIA Engineer, Lisa Hobley and Anthony Hobley - climate emergency compatriots!
06 May 2017 [09:21]
winding by Gael Vidal-Garner, Leila Vidal-Garner, Maia Vidal-Garner, Mandy Garner and IIA Engineers Ed Wheatcroft and James Pavelin
29 Apr 2017 [15:59]
winding by CSER delegates
22 Apr 2017 [08:32]
winding by 3C6 students Antoine Dupuis and George Hawkswell - first timers!
21 Apr 2017 [20:15]
What on earth happened here? [link]
15 Apr 2017 [19:00]
ADJUST: +200ms/day to 48300 and wind
08 Apr 2017 [12:06]
top-up wind
08 Apr 2017 [12:05]
ADJUST: +5000ms/day to 48100 to correct for extra weights, exactly as on 25 March
08 Apr 2017 [12:00]
I've reinstated the extra weights to the barocomp as they were on Sat March 25 - total eight extra weights - and I've superglued them in place so they don't fall off!
07 Apr 2017 [18:01]
winding with Catherine Aman and Tania Villares Balsa from Cambridge Enterprise - and some Spanish friends
07 Apr 2017 [18:00]
repositioning the fallen barometric compensator weight. No sign of mouse droppings...
06 Apr 2017 [02:10]
it looks as if another of the barometric compensator weights has fallen off. Will have to wait until winding tomorrow night to fix. I wonder if a mouse is the problem? Always seems to happen at 3am-ish.
31 Mar 2017 [08:00]
ADJUST: -300ms/day to 43100 and wind
30 Mar 2017 [14:41]
ADJUST: -4700ms/day to 43400 after one of the barometric compensator weights fell off! I removed the other one that was delicately poised. So the barocomp has a total of six extra weights (each 120g)
29 Mar 2017 [09:43]
For the record, here are instructions for Silencing the Clock [link] - useful for instance when the Choir is recording in the Chapel
26 Mar 2017 [00:03]
ADJUST: +200ms/day to 48100 fine tuning
26 Mar 2017 [00:01]
advance clock for summer time, done by Alice Wilcox
25 Mar 2017 [23:51]
winding by John Aldridge, Chris Nickolaus, Alice Wilcox, Graham Newman, Imogen Newman, Gary Walkow
25 Mar 2017 [17:45]
ADJUST: +7200ms/day to 47900 to correct for added weight to barocomp
25 Mar 2017 [17:25]
added 480g to barometric compensator (four 120g weights) to see if I can overcompensate it, as a check on its performance
21 Mar 2017 [11:25]
There was a power cut overnight. Restarted easily (no disk errors). Also a small top-up wind so we can get through to clock change at midnight on Saturday.
18 Mar 2017 [11:30]
winding with Graham Newman and Andy Burdon
18 Mar 2017 [11:20]
re-hanging the going train cable with the new quarters-advance lever with the dogleg cut-out. Works well - no more clunky winding.
16 Mar 2017 [14:30]
pendulum stopped for fitting of pendulum shaft temperature probe. Also tried to measure horizontal flexibility of the clock frame at the pendulum suspension point. Rather tricky!
15 Mar 2017 [07:45]
wind, only 24 turns, in readiness for Graham Newman and Andy Burdon on Saturday
09 Mar 2017 [15:15]
fitting of new quatrers advance lever, and partial wind
06 Mar 2017 [22:10]
wind with Adrian Poole, Chris Morley and others
01 Mar 2017 [14:30]
top-up wind during fit test for new quarters advance bar with Stefan Savage
28 Feb 2017 [18:00]
wind during filming with Gary Walkow
22 Feb 2017 [19:00]
wind (storm Doris)
15 Feb 2017 [12:15]
wind with Stefan Savage, Daniel Flack and Baba Bob-Soile. Also made some measurements and accidentally knocked the pendulum
13 Feb 2017 [17:30]
Quinn the Harris Hawk ate a pigeon and got stuck behiind the minute hand causing a 186-second stoppage. Reset with the help of Helen Shao, Renos Lyssiotis and Gary Walkow, and we did a top-up wind.
12 Feb 2017 [12:13]
computer disc crash again - restart. Really need to get this Raspberry Pi going.
10 Feb 2017 [08:00]
winding, for the first time in ages on my own - no-one turned up for a 8am wind! Also checked winding constant - 7.8 turns per day. 20 dongs per turn.
01 Feb 2017 [17:20]
winding by Michael Vanoli - very energetic! It turns out that he's from Saffron Walden and knows Graham Newman from way back.
31 Jan 2017 [15:48]
clock stopped to do an experiment, restarted at 15:57. Measuring the tilt of the clock when subject to weights.
31 Jan 2017 [12:00]
GCR=49.7s on lower layer, cold day hence high air density so bells are slow due to drag on flys
24 Jan 2017 [10:05]
the computer hard disc is in a bad way - another restart today. About time we shift to Raspberry Pi?
24 Jan 2017 [10:00]
winding by Cal Revely-Calder and Adrian Poole
16 Jan 2017 [22:05]
winding by Cath Collopy and Bill Collopy
13 Jan 2017 [18:05]
winding by Michael Fulcher (Christ Church South Yarra) and Kirsty Ross - not 8-months pregnant this time.
06 Jan 2017 [11:01]
winding by Carolyn Wilson, Juliet Harkness (as in @TimandraHarknes) Piers Wilson and Dennis Harkness - after their family party at Corpus where they have a non-clock ...
05 Jan 2017 [15:14]
not sure what's happening to the clocklogger PC - I think the hard disc is on its way out. Had to do a hard (push the button for 5 seconds) reboot. Then up came a nasty black windo saying "file system errors" ... "requires manual fsck" so I did fsck /dev/sda1 and answered yes to all the questions. End with exit and it does a reboot.
01 Jan 2017 [00:00]
correction due to the leap second - to please Keith Rodgerson!
30 Dec 2016 [13:31]
ADJUST: -300ms/day to 40700 see effect of change here [link]
30 Dec 2016 [13:30]
winding by Oliver Grigg, Paula Windsor, Adrian Grigg, Jonathan Windsor, Gaenor Jones, Sophia Jones, Neil Jones, Amy Drinkwater, Rachel Bentley Sophie Grigg - serendipitous meeting with past Trinity Engineers
27 Dec 2016 [21:37]
winding by Ingo Drewry, Matilda Gomperts Willis, Jasmine GCRCeccarelli-Drewry, Fabian Gomperts Willis, Imogen Gomperts-Mitchelson and Ian Willis - all well christmas turkey'd.
20 Dec 2016 [19:53]
winding by Portia Drewry, Jasmine Ceccarelli-Drewry and Sheila Ceccarelli - all first timers!
14 Dec 2016 [00:09]
winding by visiting Melbournians Catherine Hedding and Megan McLaughlin - Catherine did all the hard work!
10 Dec 2016 [16:50]
ADJUST: +200ms/day to 41000
10 Dec 2016 [16:48]
Winding by Olivia Cutts, Nikki Cutts, Tim Cutts, Doreen Cuerden, Ian Cuerden before the Fairhavens Christmas Concert
05 Dec 2016 [10:20]
ADJUST: +200ms/day to 40800
05 Dec 2016 [10:16]
winding with Katherine Burchell - soon after her father!
29 Nov 2016 [12:34]
reset last_drift
28 Nov 2016 [17:05]
winding by Alice Archer - makes a change from Classics!
21 Nov 2016 [08:01]
winding with Benat Gurrutxaga-Lerma
13 Nov 2016 [21:17]
winding with Gary Walkow
06 Nov 2016 [12:08]
ADJUST: -420ms/day to 40600
06 Nov 2016 [12:05]
Winding by Eleanor Kornas and Paul Milhau - good exercise before Elly's organ recital this evening!
05 Nov 2016 [17:36]
On closer inspection I see [link] that there was weather data being logged (via RS232) very sporadically, so the PC was running. For instance, on Fri 4 Nov there are 31 weather records (instead of the usual 2880 records being one record every 30 seconds). There is a data record in the weather file at 4.18am on Sat 5 Nov and again at 11.24am. Full data (every 30 seconds) resumed at 17:36:30 after the computer restart.
05 Nov 2016 [17:36]
Found the computer running but unresponsive. Hard reset, but there's a Ubuntu crash report [link] ... if anyone can figure it out for me! Possibly not important because clocklogger is running fine
03 Nov 2016 [07:00]
Not sure what happened here - a power cut? [no, see later comments] The clock was fine - of course. The computer had stopped logging data.
29 Oct 2016 [23:00]
Clock change with Graham Steed, Chris Nickolaus, Filip Szczypinski and friends
22 Oct 2016 [11:36]
ADJUST: +100ms/day to 41020
22 Oct 2016 [11:05]
Clock winding Elizabeth Bourne, Kate Bourne, Jonny Bourne, Tina Queloz, Didier Queloz @didierqueloz - on a sunny saturday
18 Oct 2016 [11:00]
GCR 47.7s on upper layer
16 Oct 2016 [11:31]
ADJUST: +420ms/day to 40920
16 Oct 2016 [11:07]
winding by Cathy Costello, John Costello - managed by Hilary Costello - from Calgary.
15 Oct 2016 [11:00]
Great Court Run, four or five 'winners' with a certain degree of corner cutting in evidence ... GCR 47.3s on upper layer, it was decided that 48.5s on lower layer was too slow.
10 Oct 2016 [21:09]
Joseph Landman, Rupert Beale @dr_beale_ and Rory Landman, last minute winders
03 Oct 2016 [09:05]
winding by Wren Archivist Jonathan Smith - excellent!
29 Sep 2016 [11:28]
visit and short wind with Ron Oxburgh after a good discussion about climate change!
25 Sep 2016 [20:08]
Winding by Daryl Burchell - first timer!
18 Sep 2016 [09:43]
Great to have Lindsay Schusman winding - she's a Big Ben guide. Lots to talk about, and to compare between these two very different but almost identical clocks.
11 Sep 2016 [17:03]
Sofia Taylor, Olivia Tidswell, Mark Burrell, Rory Little, Aaron Wienkers, Maximilian Jakobs, Lukasz Kopec, Sarah Garland, Barbara Garland, Filip Szczypinski all sweaty after Zorb football - BA Society friendly, so everybody won
05 Sep 2016 [14:20]
Thanks again to Rick Lupton, fixed weatherlogger too. He converted the old file /etc/init/clocklogger (and same for weatherlogger) to the new one /lib/systemd/system/clocklogger.service. Now start it with "sudo systemctl start clocklogger" and check what it's doing with "systemctl status clocklogger". See the logging output with "journalctl -f". Here is the command history that Rick used to make the changes [link]
05 Sep 2016 [10:20]
Thanks to Rick Lupton for fixing the problem. Apparently the latest version of Ubuntu doesn't use upstart - it's been replaced with: systemd
04 Sep 2016 [21:13]
logging stopped because of upgrade to Ubuntu 16.04.1 - not sure what's gone wrong
04 Sep 2016 [20:13]
top-up wind
02 Sep 2016 [17:09]
winding by Adeline Klotz, Aaron Wienkers and John Aldridge - we had to fix the Trinity Strike which had stopped early
26 Aug 2016 [07:05]
winding by Frank Barker
19 Aug 2016 [07:05]
winding by Frank Barker
16 Aug 2016 [08:42]
Thanks to Frank Barker for restarting
16 Aug 2016 [07:42]
for some reason the clock stopped at 8.39am (7.39am GMT). Surely not a pigeon? See this <[link]> for a 6-minute zoom in of pendulum amplitude (each dot is a 3-second tick). Rather curious that it stopped for about 20 seconds then ran on fine for about 60 seconds and then stopped for good. One theory is that the minute and hour hands interfere with each other as they pass, but these photos [link] [link] taken at 8.44am a few weeks later seem to show that it's OK
12 Aug 2016 [09:09]
winding by Meredith Hadfield, Bryony Mountfort and Mantas Kandzezauskas (who actually piked out at the last minute!)
05 Aug 2016 [09:12]
winding by Alex Woolgar-Toms
29 Jul 2016 [13:11]
winding by Ollie Price matric 1989 and Paul de Panisse after much wranglings over gyroscopic effects
26 Jul 2016 [16:21]
ADJUST: +100ms/day to 40500
23 Jul 2016 [17:04]
ADJUST: -300ms/day to 40400
22 Jul 2016 [08:05]
winding with Alex Woolgar-Toms
14 Jul 2016 [20:18]
winding with Ben Ashforth @woollybenguin from Worcestershire - the longest clock-winding journey ever!
07 Jul 2016 [11:14]
filming of winding Eugenio Polgovsky - a good excuse not to wind, but he did do the heaviest one!
07 Jul 2016 [10:55]
ADJUST: +400ms/day to 40700
30 Jun 2016 [08:15]
winding by Alex Woolgar-Toms
23 Jun 2016 [08:42]
ADJUST: +600ms/day to 40300 and top up wind.
19 Jun 2016 [11:09]
Stopping of the clock to re-align the pendulum optic sensor. Here's a detailed graph of events <[link]> It shows 3 hours' data on Sunday I did a tapping at about 10.30GMT and accidentally touched the pendulum at 10.40, then stopped the pendulum and restarted at 11.10
19 Jun 2016 [11:00]
GCR=45.5s on upper level, just after wind
19 Jun 2016 [10:55]
Top-up wind by Phil Deakin, Fiona Burke, Joan Lasenby - witnessing a tapping of the pendulum, and accidental touch of the pendulum
17 Jun 2016 [17:10]
tapping the pendulum
15 Jun 2016 [18:00]
tapping rather more vigorously. A big drop in going! Maybe dislodged a sticking zinc tube in the pendulum, after all my insistence that it wasn't sticking. Maybe we need to take the pendulum apart again.
15 Jun 2016 [17:30]
tapping the pendulum always causes s drop in amplitude of swing. Never an increase. Is this a clue? Here's a detailed graph of events <[link]> It's zoomed into 2 hours 5-7pm GMT Note a tapping at about 17:30 caused a step drop in amplitude but a step rise in drift. I'm not sure I understand this. Then a more vigorous tapping at 17:50 caused a drop in amplitude but a step change in going. Is this the zinc tube unsticking?! Then a few minutes later, I don't think I did anything...!
14 Jun 2016 [22:00]
The other rather nice thing is that the tapping reducing pendulum amplitude increases going. This seems exactly in accordance with pedulum theory [link] so where does this leave the theory about amplitude increase being casued by the sensor being off centre?
14 Jun 2016 [22:00]
OK, so I went up the tower again tonight (with Paul Ashley to watch the St John's fireworks) and gave the pendulum hanger a second tapping. Yet another drop in amplitude (see below). If the theory is correct then as the temperature stabilises the amplitude ought to drop again and tapping should give upward steps. This should satisfy John Hodgson - I don't think economists are very good at making predictions! [link]
14 Jun 2016 [22:15]
changing the suspension would count, in my view, as irreversible, because if it works then who would want to put back the old one? And there's not much point in going to the trouble (and it would be a lot of work) if there's no intention of using it. The barometric compensator is fine because it can be removed in under 5 minutes and the clock is back to its original state. Likewise the teflon tape and graphite powder. The only thing I don't like about the vibrator idea is that it needs a battery power supply. I'm wondering about energy harvesting from the bell flies to charge up a battery...,
14 Jun 2016 [22:15]
When I tap it I tap the shaft horizontally back and forth the 0.5mm a couple of times. PTFE is convenient. When I first put it in about a year ago (look at diary comments April to June 2015) it seemed to make a difference. Perhaps the graphite powder too. Not sure which! And for mods like knife edges, etc, they'd have to support the 100kg weight of pendulum. A contact area of 20mm^2 leads to stress of 50MPa so the "knife edges" would be quite thick. I suspect the 19c clock makers would have done it this way if it was a better solution. I also wonder about creating a third lightly damped degree of freedom. Torsion is already coupling with E-W swing, and adding N-S swing at a close frequency will be complex. I'm also reluctant to make irreversible changes to this heritage clock. The idea of a vibrator has crossed my mind, something I'll try if lubrication isn't enough.
14 Jun 2016 [22:15]
Some new information: I tapped the pendulum hanger and the pendulum amplitude suddenly reduced. Aha! I think the tower tilt theory is looking stronger. The optic sensor that measures amplitude is mounted on one side of the pendulum shaft (see photo [link] ) It's a top down view, so the sensor is at the bottom of the photo. Note that the pendulum suspension is in vee blocks so that if the tower tilts then it ought to remain swinging in a vertical plane. But friction (which I've tried to reduce with teflon tape and graphite powder) prevents the pendulum from being perfectly vertical. But if it swings out of verticla it also twists. Now, the sensor is off centre so twist registers as a change in amplitiude. So knocking the hanger has made the swing vertical and twist is reduced. In fact from this it is possible to decuce direction of tower tilt, and it's consistent with warming on the sunny side. Getting there!
14 Jun 2016 [22:15]
Thermal diffusivity is a useful parameter to describe heat flow through the stone walls. It is about 1e-6 m^2/s. This means that a step change in temperature will take 1 second to reach a depth of 1mm, and 3 days to penetrate half a metre. This is why I'm thinking that a gradual rate of change of temperature (over days) can cause tower tilt.
14 Jun 2016 [22:15]
The clock itself is an engineering marvel, accurate to better than 1 second per month. Most of the knots have been combed out, see here for example [link] and what remains are curious glitches that wouldn't even be noticed unless we'd bothered to look. What is great about this is the opportunity to revisit and admire the fabulous achievements of 100s of years of engineers and scientists and to see what little we can contribute ourselves.
14 Jun 2016 [22:15]
tapping the pendulum hanger to check if the twist effect is still happenning - and yes it is: [link]
14 Jun 2016 [13:30]
winding with Sir Jonathan Ive and family and with Roberto Cippolla. Also tapping the pendulum hanger to see if there is a tower tilt effect.
09 Jun 2016 [07:55]
Winding with Anna Basaj
06 Jun 2016 [14:00]
I have been thinking of sticking of the zinc-steep compensation in the pendulum tube. There are several reasons for NOT thinking it is a sticking zinc tube. 1. It is not sudden - it happened over 8 hours from 10am to 6pm <[link]> The clock normally responds very quickly to even the tiniest of mechanical step changes, eg <[link]> which was an adjustment on 1 May. 2. If the zinc is sticking then we would expect under-compensation, ie slower going as temperature rises. It seems to be faster, so it is the wrong way round. 3. It is a small effect, perhaps 200ms/day fast at the moment. Given that an uncompensated pendulum would be -600ms/day/C then if it were sticking we would expect something bigger 4. stress = E * alpha * dT and for zinc E=100GPa and alpha=30e-6/C , say. Then for a 1C temp rise stress = 3MPa, and with a cross section are of about 1000mm^2 then that is an axial force of 3000N, or 300kg. I do not think there is enough friction to sustain this. When we removed the zinc tube a while back it came out relatively easily. 5. There is a small cyclic stress pulse every 1.5 seconds due to centrifugal force. It s about 2N for a 100kg pendulum bob. This ought to be helping to dislodge sticking. But what can it be???? One clue, perhaps, is that the change occurred during a maximum of "rate of change" of temperature. But why?
06 Jun 2016 [14:00]
To give you an idea of what is "normal" then here is data since November. htGCRtp:// Note that the red and blue arrows indicate intentional adjustments, but that the recent glitch is really one of many, perhaps the most dramatic in recent months. You can change the date back a few years if you want. Also you can look at air pressure, humidity, swing amplitude, etc. Simon mentioned spiders - search for that in comments too. The spider incident was, I think, when a web was spun in the pendulum chamber. the pendulum amplitude reduced which speeds the clock up. But this time the amplitude has not changed, so it is not spiders again - I think.
06 Jun 2016 [14:00]
Things like pigeons standing on the hands, wind, snow etc do not have an effect - that is the beauty of the gravity escapement. Likewise lubrication of gears etc. The effect of opening doors - do a search for "the bedmaker effect" - is understood too, after a fashion. The clock dial faces south and it is definitely possible that sunshine has an effect, but not as one would expect. I have a student (from St Johns) this year exploring the effect of warming of the south-facing wall, thermal expansion and therefore tower tilting. The pendulum develops a noticable twist from time to time and this I think is due to tower tilt. It would be good to see if tower tilt, pendulum twist and changes in going are correlated
06 Jun 2016 [14:00]
so what has caused this dramatic change in going? [link] Temperature compensation is good. Pressure also (air density affects buoyancy). Humidity is a small effect, humidity in this unheated room is fairly constant. There are step changes, like on 6 June. Still stron is the theory that sunshine on south-facing wall causes thermal expansion and tower tilt. I have a final-year project student (from St Johns !) to measure this effect, strarting October.
05 Jun 2016 [12:08]
clock tour for the winner of the Rag Auction: Andrew Sellek, Finn Kristensen, Anthony Wong, Noah Porcelli, Jess Young, Jess Callaghan, Daniel Thompson, Yuen Ng, Toby Henley Smith
03 Jun 2016 [08:04]
Winding by Tit hall engineers Isaac Uden, Micheala Chan, Nathan Clark and Joe Myescough from Windfall films!
28 May 2016 [17:00]
Winding by Nick Westby and Syuko Kato with Chris Nickolaus
25 May 2016 [08:44]
winding after a pedal-punt session with Julia Greenaway @juliacgreenaway, Ed Few, Barnaby Walker and Fiona Holland
17 May 2016 [22:14]
after Fairhavens, winding by Pip Matthews @orangepip86 and John Aldridge @jpsaldridge - always good to have help!
15 May 2016 [11:21]
visit by Janie Maxwell from Melbourne. She asked lots of great questions!
10 May 2016 [14:20]
ADJUST: -410ms/day to 39700 - and a wind
04 May 2016 [20:49]
Impromptu winding: Eriks Esenvalds @eriks_esenvalds , Inese Esenvalde, David Baulcombe @dcb40 , Maike Stam, Andrew Crawford, Adam Boise
01 May 2016 [21:02]
Great 'night-winders': Imogen Hipkin-Holland, Emma Gee Olmedilla, Carmen Olmedilla Herrero. Andrew Gee, Roberto Cipolla, Yvonne Higgons, Robin Higgons,Stuart Hendry, Alison Hendry, Liesbeth Blom
01 May 2016 [20:58]
ADJUST: +500ms/day to 40110 This is the first adjustment since 23 November. It is truly remarkable that the clock has run for 160 days before drifting outside of the +/- 3 seconds leeway that I give it. It seems that the temperature compensation is not perfect. Perhaps I need an extra 30ms/day per degree [link]
24 Apr 2016 [10:38]
Excellent winders: Olivia Cutts (youngest ever?), Louis Place, Nikki Cutts, Tim Cutts, Andrew Smith, Ray Morley, Louise Place
21 Apr 2016 [21:55]
winding by Trinity College Melbourne Alumni, fearless leader Ken Hinchcliff, Shivaan Bardolia, Nicholas Langford (@njwlangford), Georgina Baker, Taylor Callaghan, Michael Li, Alex Ross, Kirsty Ross
18 Apr 2016 [09:09]
winding by Duncan Malthouse-Hobbs @dunk1406 and Andrei Popovici - Trinity Computer lot!
10 Apr 2016 [16:43]
winding with help from Chris Nickolaus - lots of chat about tilting towers ...
03 Apr 2016 [11:08]
winding by Tamsin Cowley, Ian Cowley and Jasper Cowley with Chris Nickolaus
01 Apr 2016 [12:00]
Alex Woolgar-Toms top-up winding with friends
27 Mar 2016 [00:05]
clock change by Alex Woolgar-Toms and Chris Nickolaus - many thanks! And a full wind too
24 Mar 2016 [12:05]
instructions for the clock change - fiddling a bit with the escapement
19 Mar 2016 [14:15]
top up wind
18 Mar 2016 [18:03]
Winding by Trinity Catering Duo - Jessica Duck @fitduck and Peter Mezei
11 Mar 2016 [18:10]
winding by Chris Nickolaus - on a beautiful spring evening.
04 Mar 2016 [08:03]
Early wind by Arsalan Harris
25 Feb 2016 [21:02]
winding by David Lavender
18 Feb 2016 [08:07]
winding by John Ledger - part of the Logie Baird team!
10 Feb 2016 [21:33]
winding by the Combustion Group: Philip Sitte, Anna-Maria Kypraiou, Andrea Giusti, Harsha, Colleen Stuart, Patton Allison, Pedro Magalhaes de Oliveira, Jenni Sidey @jennimsidey
03 Feb 2016 [18:58]
winding with Felicity Lamacraft, Celeste Lamacraft, Arrate Molina and Austen Lamacraft - all very excitable inversely proportional to age!
27 Jan 2016 [17:30]
winding ably assisted by Terry Black from Windfall Films - all for a documentary about the first television broadcast in 1936. Thanks also to Peter Gauvain behind the camera and Henry Hocking on sound
20 Jan 2016 [11:23]
Thanks to Peter Windmill for winding at the last minute - and for correcting the bells that went out of synch
12 Jan 2016 [23:07]
winding after Fairhavens with Stephen Watson - Emmanuel College
05 Jan 2016 [18:11]
winding by Andy Jude and Hilary Costello - first for 2016
29 Dec 2015 [17:43]
Winders: Julian Cooling, Karen Bass and Chris Nickolaus, last wind of 2015.
22 Dec 2015 [21:27]
Clock winding by Deah Dhaliwal, Anya Dhaliwal and Sam Dhaliwal, shown the ropes by Hilary Costello - thanks!
15 Dec 2015 [21:00]
Winding by Rick Lupton - thanks!
08 Dec 2015 [22:39]
after three pints of Pegasus from the Maypole (in own glasses) winding by Ben Sparks @sparksmaths and Seb Falk @seb_falk
01 Dec 2015 [09:08]
Nick Denyer girding his loins for essay marking
30 Nov 2015 [16:13]
visit by Owen Ryder and Peter Stitt from Cummins Turbo - true mechanical engineers!
23 Nov 2015 [21:36]
yet more, from Peterhouse, Trinity and other colleges (Queens' perhaps?) Basil Mustafa, Ethan Silverstone @ethanjdanger, Ciara Norris @ciaranorris18, Fran Penrose @franpenrose, Farzana Huysman @farzanahuysman, Olufolajimi Babasola @folajimi_, Andreas Orphanou, Ruth Augarde, Ben Ferris @benaferris ,
23 Nov 2015 [21:35]
ADJUST: -90ms/day to 39610 - on advice from a Queens' student
16 Nov 2015 [09:16]
more Part IA Lego engineers! See Yee Tan, Yi Chao Ong, Chen Chun Chai (not clock builders!)
09 Nov 2015 [09:43]
Some observations on the effectiveness of the barometric compensator when it was removed for 5 weeks this year. July-Aug (compensator in place): <[link]> Sept-Oct (compensator absent): <[link]> Oct-Nov (compensator reinstated): <[link]>
08 Nov 2015 [21:33]
and winding by Emma Gee Olmedilla, Mariana Gee Olmedilla, Carmen Olmedilla Herrero and Andrew Gee
08 Nov 2015 [21:09]
Winding by IA lego engineers: Lizzi Hawkins, Elena Rastorgueva, Shrinikesh Arulselvan, Nimesh Patel, Seb Dickson,
01 Nov 2015 [11:11]
Winding by German and Danish Othello players: Matthias Berg, Erik Lund Jensen, Anita Raddatz, Ernst Raddatz and Imre Leader
25 Oct 2015 [00:00]
Clock Change for end of summer time, thanks to Alex Woolgar-Toms and Chris Nicklaus with Zoran Hadzhiivanov and Jim Minter

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Contact:, Trinity College, Cambridge