NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Prime Meridian on the move
From: Bruce J. Pennino
Date: 2016 Jan 15, 21:39 -0500
Bruce
-
exaggerate the DoV by a factor of 100 in the optical plummet's field of
view---problem solved
Cheers,
Peter
From: Bruce J. Pennino
Date: 2016 Jan 15, 21:39 -0500
Seems like everything is moving all the time. Continental drift,
internal molten mass, glaciers melting, mountains going up/down , giant rivers
with moving banks, north magnetic pole moving , and all the other stuff
that would cause “brain ache”. Hard to believe “0” will ever be truly fixed
(compared to what).
When I made the obligatory trip to Greenwich a few years ago I heard
a great presentation.. Most interesting thing for me was the
following story....maybe true....maybe not...... To quote more or less from
memory: “ New observatory finished, telescope anchored in place, windows
all done, chief astronomer does observations. He found that a window was
located improperly so that Zero longitude could not be sighted by a couple of
inches, or something like that. So 0 longitude was fudged by a small
distance and the line was set”. Anyone else confirm this story for tourists?
Happy and Healthy New Year to all
Bruce
From: Peter Monta
Sent: Friday, January 15, 2016 10:37 AM
Subject: [NavList] Re: Prime Meridian on the move
While I'm in tourist-exhibit-design mode:
- show the ITRF
velocity as well, so tourists can get a gut feel for tectonic motion
