Finding your location without GPS is not all that difficult.
You need a quality theodolite, but even an ordinary one will read to
1 second of arc.
You observe circumpolar stars at night to obtain a true azimuth.
(North and South)
and also the latitude by the inclination of the pole.
On a
Finding your location without GPS is not all that difficult.
You need a quality theodolite, but even an ordinary one will read to
1 second of arc.
Ordinary? You mean something like a Wild T-2 or Kern DKM-2. Even then
getting close to 1 arc-second requires a lot of care.
You observe
On 26/01/2012, at 2:49 AM, J. Forster wrote:
Finding your location without GPS is not all that difficult.
You need a quality theodolite, but even an ordinary one will read to
1 second of arc.
Ordinary? You mean something like a Wild T-2 or Kern DKM-2. Even then
getting close to 1 arc-second
Ordinary? You mean something like a Wild T-2 or Kern DKM-2. Even then
getting close to 1 arc-second requires a lot of care.
A wild T1 reads directly to 6 seconds, but with repetition will get 1
second.
Unlike digital instruments you need a little bit of skill and
persistence to get the best
Moin,
All this talk about telling the time using stars or the sun made me wonder
how did people tell what position their telescopes had back in the days
before GPS? I know that most countries established a coordinate system
in the last 100-200 years. But astronomy has been around much longer and
In message 20120124115848.312d60bd4fccce4f3e71c...@kinali.ch, Attila Kinali w
rites:
All this talk about telling the time using stars or the sun made me wonder
how did people tell what position their telescopes had back in the days
before GPS?
Back then the stars were the coordinate system and
On Tue, 24 Jan 2012 11:04:08 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 20120124115848.312d60bd4fccce4f3e71c...@kinali.ch, Attila Kinali
w
rites:
All this talk about telling the time using stars or the sun made me wonder
how did people tell what position their
In message 20120124121642.4a8ad1def54bc32cca928...@kinali.ch, Attila Kinali w
rites:
On Tue, 24 Jan 2012 11:04:08 +
But how do you untangle longitude and time? How do you know that you
are looking exactly south (or north)?
North/South can be done by timing (widely spaced in inclination)
On Tue, Jan 24, 2012 at 3:16 AM, Attila Kinali att...@kinali.ch wrote:
On Tue, 24 Jan 2012 11:04:08 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 20120124115848.312d60bd4fccce4f3e71c...@kinali.ch, Attila
Kinali w
rites:
All this talk about telling the time using stars or
Yes, the first real push was the Longitude Act (1714) and the Harrison's
clocks.
On Tue, Jan 24, 2012 at 5:36 PM, Chris Albertson
albertson.ch...@gmail.comwrote:
On Tue, Jan 24, 2012 at 3:16 AM, Attila Kinali att...@kinali.ch wrote:
On Tue, 24 Jan 2012 11:04:08 +
Poul-Henning Kamp
Maybe the Longitude Act was issued also because of the disaster occured in
1707 due to a navigation error: the Royal Navy fleet lost 4 of its 15 ships.
On Tue, Jan 24, 2012 at 5:50 PM, Azelio Boriani azelio.bori...@screen.itwrote:
Yes, the first real push was the Longitude Act (1714) and the
and frequency measurement
time-nuts@febo.com
Sent: Tuesday, January 24, 2012 10:36 AM
Subject: Re: [time-nuts] establishing your position w/o gps
On Tue, Jan 24, 2012 at 3:16 AM, Attila Kinali att...@kinali.ch wrote:
On Tue, 24 Jan 2012 11:04:08 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote
! And it
wasn't done overnight!
Lee K9WRU
- Original Message - From: Chris Albertson
albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Tuesday, January 24, 2012 10:36 AM
Subject: Re: [time-nuts] establishing your position
I think James Burke discussed these clocks in one of his documentary
series. Besides not using a pendulum, they were temperature
compensated by using materials with opposite temperature coefficients
of expansion and then gimbaled for use on a rolling and pitching ship.
Oddly enough, the phase
On Tue, 24 Jan 2012 11:05:58 -0600
Lee Mushel herbe...@centurytel.net wrote:
If you're looking for a really interesting topic to read about, the
development of an accurate ship-board clock is really fascinating! And it
wasn't done overnight!
If you have a few references on books to read,
If you want to try your hand at position determination in the pre
radio nav days you can buy a studen sextent It's a low cost plastic
instrument sells for about $60. Better ones start at $200 with $500
to $800 for a good one. But it required much pratice and training to
outgrow the plastic
--
From: Chris Albertson albertson.ch...@gmail.com
Sent: Tuesday, January 24, 2012 11:36 AM
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] establishing your position w/o gps
On Tue, Jan 24, 2012 at 3:16 AM, Attila Kinali att...@kinali.ch
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] establishing your position w/o gps
If you want to try your hand at position determination in the pre
radio nav days you can buy a studen sextent It's a low cost plastic
instrument sells for about $60. Better ones
your position w/o gps
On Tue, Jan 24, 2012 at 3:16 AM, Attila Kinali att...@kinali.ch wrote:
On Tue, 24 Jan 2012 11:04:08 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 20120124115848.312d60bd4fccce4f3e71c...@kinali.ch, Attila
Kinali w
rites:
All this talk about telling
[snip]
Then you measure
distance by tossing a big chunk of lumber overboard with a measured
rope tied to it. The captains hated doing math by hand so they
calibrated the rope by tieing knots at intervals so the natural unit
was one arc minute at the equator and called it a knot.
Nope. A
From: Bob Camp li...@rtty.us
To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com
Sent: Tuesday, January 24, 2012 10:13 AM
Subject: Re: [time-nuts] establishing your position w/o gps
Hi
If you spend some time on the auction sites you can find some
On Tue, Jan 24, 2012 at 10:31 AM, J. Forster j...@quikus.com wrote:
Nope. A knot is a unit of velocity, not didtance.
A knot is 1 nautical mile per hour
A nautical mile is that distance, subtended at the earth's surface at
the equator, by 1 arc-minute.
If somebody tells you the ship was
Then, as now, a knot is a unit of speed, not distance! If you counted 7
knots in a standard song, it was still speed.
-John
==
On Tue, Jan 24, 2012 at 10:31 AM, J. Forster j...@quikus.com wrote:
Nope. A knot is a unit of velocity, not didtance.
A knot is 1 nautical mile per
Subject: Re: [time-nuts] establishing your position w/o gps
have you ever tried to measure an angular distance using a hand held
instrument while standing on the deck of a moving boat in the open
ocean? try it and you will see why they wanted a clock. You
really can't measure an arc minute
But how do you untangle longitude and time? How do you know that you are
looking exactly south (or north)?
If I understand what you are asking, it's the same problem as navigating a
ship without a clock.
Classic navigation with a sextant needs a clock and sightings on 3 objects in
the sky.
Hi:
The basic way to find your location anywhere in the world is to use a photo
sensor.
This is the method used on tagged fish. The light level is logged and time stamped probably using a watch crystal.
When the fish is caught the logger data is read out.
Have Fun,
Brooke Clarke
For a rough determination; you are facing due south, or due north when the
elevation of a celestial body stops increasing with time. The elevation is
highest when the body is on the observer's local meridian. There are
exceptions, for instance when observing a body below Polaris, then the body
On 1/24/12 9:48 AM, Chris Albertson wrote:
If you want to try your hand at position determination in the pre
radio nav days you can buy a studen sextent It's a low cost plastic
instrument sells for about $60.
That's the Davis Mark 3 (which is basically a copy of a lifeboat
sextant). $50 from
On 1/24/12 9:46 AM, Attila Kinali wrote:
On Tue, 24 Jan 2012 11:05:58 -0600
Lee Mushelherbe...@centurytel.net wrote:
If you're looking for a really interesting topic to read about, the
development of an accurate ship-board clock is really fascinating! And it
wasn't done overnight!
If you
On 1/24/12 10:26 AM, Chris Albertson wrote:
have you ever tried to measure an angular distance using a hand held
instrument while standing on the deck of a moving boat in the open
ocean? try it and you will see why they wanted a clock. You
really can't measure an arc minute reliably we
On 1/24/12 3:19 PM, J. Forster wrote:
Is the USNO almana/ephemeris still published in hard copy every year? That
had moon timing, etc.
You can download pieces from the Astronomical Applications website at USNO.
Or you can buy a copy of the Nautical Almanac for about $20 from a
variety of
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