[time-nuts] Re: Where do people get the time?

[Tom Van Baak]

Hal Murray wrote:
 > where do you get the time?

The new years celebrations last night remind me of another source of 
time: time balls.

Although a bit of nostalgia these days or even a joke, time balls were 
clever, precise, and a critical part of naval infrastructure in the 19th 
century, lasting well into the 20th century, and still operational daily 
in Greenwich (not right now due to refurbishment). It falls into the 
category of "time dissemination"; you know, WWV, GPS, UTC, NTP, and all.

The sound of church bells gave approximate time, partly because their 
use case didn't require high precision and partly because sound travels 
only one foot per millisecond. Related: starter pistols at track events; 
clapperboards on movie sets; timing thunderstorms with lightning.

But light, as you know, travels literally a million times faster, one 
foot per nanosecond. Thus the optics of a time ball solved the latency 
problem of setting chronometers onboard ships in the bay. Fun fact: The 
Beagle (of Charles Darwin fame) carried 25 chronometers. This is every 
time nuts justification for having so many clocks at home. ;-)

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If you want a fun timely project I'm waiting for a time nut to make a 
GPS controlled desktop Arduino time ball. With clever design it could 
re-arm itself and mark the precise time as often as once a minute 
instead of once an hour or once a day.

Alternatively, if you allow the ball to free-fall 16 feet it takes 
exactly one second. With clever design and multiple balls you could make 
a continuous 1BPS (one ball per second) clock where each ground hit 
exactly triggers the next ball release. This would get you front page on 
hackaday. Lots of time nut fun looking at jitter and drift, at 
temperature and pressure effects. And of course the ADEV would be 
priceless. Seriously, some mechanical clocks teach you more about the 
art of clock measurement and data analysis than a boring atomic 
frequency standard or GPSDO.

Welcome to 2022, and may we all have a better time this year.

/tvb

Time ball rabbit hole:

https://en.wikipedia.org/wiki/List_of_chronometers_on_HMS_Beagle
https://en.wikipedia.org/wiki/Ship%27s_chronometer_from_HMS_Beagle

https://en.wikipedia.org/wiki/Time_ball

https://www.bbc.com/news/uk-england-humber-58559814
"Time balls: The rise and fall of a timekeeping icon"

https://www.nytimes.com/2004/12/30/opinion/a-brief-history-of-time-balls.html
"A Brief History of Time Balls"

https://nmmc.co.uk/wp-content/uploads/2016/04/120330_The_Falmouth_Timeball.pdf
"The Falmouth Time Ball", by Ronald S Hawkins  [ superb historical & 
technical details ]

https://hs-ny.org/schedule/2019/5/6/the-ups-and-downs-of-the-greenwich-time-ball-an-overview-of-its-history-mechanics-and-upkeep
https://youtu.be/ubvmCWet6iU

https://journals.sagepub.com/doi/abs/10.1177/002182868101200301
"The First Time Balls"
Journal for the History of Astronomy

https://adsabs.harvard.edu/full/1970JBAA...80..208H
"The Story of Greenwich Time"

https://www.bbc.com/travel/article/20191212-the-invention-that-inspired-a-new-york-tradition
"The invention that inspired a New York tradition"

https://www.xyht.com/gnsslocation-tech/the-clocks-at-the-center-of-the-universe/
"The Clock(s) at the Center of the Universe"

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