[time-nuts] Measurements
Ulrich Bangert
df6jb at ulrich-bangert.de
Sun Aug 23 09:14:12 UTC 2009
Sanjeev,
> That sounds like the Repeating Theodolite, used for the
> survey from Dunkirk <-> Paris <-> Barcelona
Exactly!
Thanks for your help
Ulrich
> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Sanjeev Gupta
> Gesendet: Samstag, 22. August 2009 10:56
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Measurements
>
>
> On Sat, Aug 22, 2009 at 15:19, Ulrich Bangert
> <df6jb at ulrich-bangert.de>wrote:
>
> > Which in turn lead to the invention of a new class of surveyor
> > instruments, which in turn enabled the French to measure
> the distance
> > from the equator to the north pole (assumed to be 1/4 of the
> > circumference) with a precision that must be admired even
> from a today
> > point of view. I do not know the english term for it but in German
> > these instruments are called "Repetitionskreis". You can
> find a pictue
> > of one here:
> >
> >
> >
> http://www.bistumsmuseen-regensburg.de/html/ausstellungen_moenche_repe
> > tition
> >
> skreis.htm<http://www.bistumsmuseen-regensburg.de/html/ausstel
> lungen_moenche_repetition%0Askreis.htm>
> >
>
> That sounds like the Repeating Theodolite, used for the
> survey from Dunkirk <-> Paris <-> Barcelona
>
> http://en.wikipedia.org/wiki/Repeating_circle
>
> The basic idea is to mark out repeatedly the angle to be
> measured, but actually measure the sum, _only_ at the end,
> which you then divide. It gives you the arithmetic mean of
> the value directly. The major advantage over doing this
> mechanically, rather than adding it up in your notebook, is a
> that you have reduced the least-count of your graduated scale.
>
>
> --
> Sanjeev Gupta
> +65 98551208 http://www.linkedin.com/in/ghane
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