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Subject: Re: Astro Compass History /Sun Compasses
From: Brian Whatcott (betwys@XXX.XXX)
Date: Tue Oct 29 2002 - 19:48:36 EST
[posting originally rejected as a duplicate post -
subject & last line changed]
Robert is posting from the far Northern Canada area of Nunuvet
I was surprised to find, when he took pity on a novice user of
the Mark 2 and mailed me a CD copy of the User handbook -
for which I am truly grateful.
At his urging, I offer this URL (below) which points to an interesting
informal history of some sun-compasses, which stretch back
a little further than I expected.
Sincerely
Brian W
A bilingual history of sun compasses:
<http://www.atco-fr.com/cadrans/navigation/navi_uk.php3>
At 05:46 PM 10/29/02, Robert Eno wrote:
>Greetings List,
>
>I did some digging about this question which came up about one month ago.
>I got an answer of sorts, though not a totally satisfactory answer.
>
>My acquaintance is an authority on Arctic air navigation because he was a
>pioneer in this field in the 1940's and 1950's. Here's what he had to say:
>
>-----------------
>The first appearance of a "sun compass" (the forerunner to the astro
>compass), occurred in 1917 when the American patent was issued for a
>transparent sundial to be mounted in the wing above the pilot. It required
>further development and appeared to have been dropped by the designer.
>
>With an interest in polar flying, and attendant problems of using the
>magnetic compass near the magnetic pole, attention was directed towards
>perfecting sun compasses incorporating a clock running on solar time. In
>the mid 1920's Albert Bumstead, of the National Geographic Society, devised
>one for Byrd's use on his northern flights in 1925. At the same time,
>Goerz, a German firm, developed a similar compass for use by Amundsen and
>Ellesworth in the arctic in 1925. Throughout the 1920's and 1930's, up to
>W.W.11, one or the other of the sun compasses was used on high latitude
>flights.
>
>By W.W.11, the astro compass, a derivative of the sun compass, was in use
>and became quite popular as aircraft heading could be determined from any
>celestial body whose position could be computed from an almanac.
>
>The design of the astro compass appeared to have not changed to any degree
>during W.W.11 and after. The American and British produced compasses, as
>far as I remember, were identical. For some reason unknown to me the
>British compass was referred to as RAF Astro Compass MK 11. I suspect the
>initial patents were American as they were involved in more long range
>flying just prior to the war than the British.
>---------------------
>
>So there you have it gentlemen (and ladies).
>
>I will keep the list posted on any additional information that I manage to
>dig up. Of course this does not mean the rest of you should be sitting by
>waiting for my pronouncements. I would certainly welcome any additional
>information that might be out there.
/snip/
>cheers,
>
>Robert
..
Brian Whatcott
Altus OK Eureka!
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