Re: [Phys-L] Allan deviation

[Bennett <bennett@oakland.edu>]

I am visiting my Niece in New Jersey.

I am observing her Grandfather clock.The pendulum hangs by a  very thin
brass strip,  about 3/4" wide in the top 15 inches, and an array of
parallel rods below, and a large disk.

When I look from the side. the disk tends to twist, at a faster rate and
seemingly erratically.

   Very Interesting!

I have taken pictures and will try to enlarge them when I get home.

On Sun, Jul 12, 2015 at 4:28 PM, Bernard Cleyet <bernard@cleyet.org> wrote:

> Very interesting -- as an amateur horologist, I've in the last week
> advanced to measuring the stability of clocks. (1)
>
> Fascinating, as clocks are subject to more than just "white" noise.   In
> my opinion the dean of horologists is Philip Woodward who discusses Allan
> deviation, (2) which I've used to analyse the Trinity tower clock
> (Cambridge) and the Santa Barbara Court House tower clock. (3)
>
> So any of you familiar w/ this method?
>
>
> 1,  Being computer challenged, I necessarily manually use Kaleidagraph's
> "spread sheet".
> 2,  In Rawlings (3rd ed.) and Woodward on Time.
>
> https://en.wikipedia.org/wiki/Philip_Woodward
>
> 3,  Data on line.
>
> Santa Barbara Courthouse Clock
>
> http://www.bisnoschallgallery.com/microset/data/
>
>
> The Trinity Clock
>
>
>
> http://trin-hosts.trin.cam.ac.uk/clock/?menu_option=data&from=03/04/2009&channel=drift&channel2=0&to=15/04/2009&scale=auto&type=two
>
> bc thinks this is "up JD's alley".
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