[time-nuts] Information on the Danjon Astrolab

Magnus Danielson cfmd at bredband.net
Tue Aug 8 04:23:23 EDT 2006


From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
Subject: Re: [time-nuts] Information on the Danjon Astrolab
Date: Tue, 08 Aug 2006 07:59:00 +0000
Message-ID: <53121.1155023940 at critter.freebsd.dk>

> In message <7ntf7JA6qD2EFwuF at g8kbz.demon.co.uk>, Geoff Powell writes:
> 
> >IIRC, the Danjon astrolabe uses a mercury pool, and a semi-reflecting
> >prism.
> 
> Hmm, but doesn't the local value of "horizontal" affect the precision
> also ?
> 
> You would really need to know the direction of local gravity for
> this to be any good...

Down? :-)

Wouln't a number of measurements and comparision with other methods and
measurements help to reveal such deviations? Then again, question is if the
deviation is so large that it has a real impact.

Cheers,
Magnus



More information about the time-nuts mailing list