[time-nuts] Crude Survey Technique

Robert Atkinson robert8rpi at yahoo.co.uk
Fri Nov 22 02:32:16 EST 2013


I'd also go for a compass if you want magnetic north, but then I have a good one, a "medium landing compass". Mine dates from WWII but they are still made http://www.sirs.co.uk/ground/landing_compasses/patt2/landing_resource
These are used to align the standbay and remote reading compasses on aircraft. Good to half a degree. If you need better ther is the Watts Datum Compass.
 
Robert G8RPI.
 
 From: Chris Albertson <albertson.chris at gmail.com>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
Sent: Thursday, 21 November 2013, 23:28
Subject: Re: [time-nuts] Crude Survey Technique
  

On Thu, Nov 21, 2013 at 11:11 AM, Don Latham <djl at montana.com> wrote:
> Lord no, John. No red wagon is needed. Use a pole and the equation of
> time, and a good watch or clock. At local noon, a shadow will be a n-s
> line.

How accurate do you need to be?   The above requires a very tall pole
to case a 300 foot long shadow.  Then you have to be quick to measure
because the Earth turns at  .25 degrees per minute.

If you need a very tall pole that is 100% vertical then hang a
weighted rope from a tall support.  Then go to the other end and watch
the seconds tick down.

A GOOD magnetic compass can do this job too.  Easier then finding s
1,000 food tall pole.   The better compasses have some kind of optical
aid for sighting a line.

-- 

Chris Albertson
Redondo Beach, California
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