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Re: Dream Choice of Sextant
From: Joel Jacobs
Date: 2005 Aug 8, 16:01 +0000
From: Joel Jacobs
Date: 2005 Aug 8, 16:01 +0000
FYI,
There were a few British sextants made in Sterling Silver.
Joel Jacobs
--
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http://www.landandseacollection.com
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http://www.landandseacollection.com
-------------- Original message from John Simmonds <seeka@IINET.NET.AU>: --------------
biggest problem with stainless steels is cost of manufacture, and don't kid yourself that it would be corrosion free :)the thing would also be very heavyJohn
live every day like it may be your last .. cause one day it will be
On Mon, 8 Aug 2005 07:39:51 -0400, Robert Eno wrote:
> I know my choice lies outside the bounds of what you described but
> my dream choice of sextant would be a C.Plath design in which all
> of the components are constructed from 316 stainless steel. I often
> wonder why no one ever thought of using this material for a
> sextant. Perhaps because it cannot be cast or perhaps because
> stainless steel is more prone to ther! mal changes than bronze or
> brass.
>
> Robert
>
>
> ----- Original Message -----
> From: "Mike Hannibal" <pelorus32@YAHOO.COM.AU>
> To: <NAVIGATION-L@LISTSERV.WEBKAHUNA.COM>
> Sent: Monday, August 08, 2005 2:43 AM
> Subject: Dream Choice of Sextant
>
>
>> If you had a choice between a C&P Horizon Ultra and a
>> C&P Pelorus which would you choose? Money isn't the
>> issue.
>>
>> The use is the full breadth of uses to which you might put a
>> sextant with an equal balance between
>> star/planet sights, sun sights and coastal nav stuff - distance
>> off, horizontal bearing etc.
>>
>> For those unfamiliar the key differences between the
>> two instruments are:
>>
>> 1) both use the same frame and "running gear";
>>
>> 2) the Horizon Ultra has a whole horizon mirror,
>> polarisers in both sets of shade glasses and
>> Schueler's double prism to get verticality right. In
>> other words it's a specialist sun machine;
>>
>> 3) the Pelorus has standard shades, an astigmatiser
>> for stars and planets, and an unusual horizon mirror
>> that is about 70% silvered in the a centre vertical
>> strip and unsilvered on either side. It is designed to be very
>> effective with dim stars but still OK brighter objects.
>>
>> I guess my current thinking is that t! he polarisers are nice and
>> make sun brightness and horizon clarity very easy to get just
>> right but that the Polaris is
>> proabably better for stars as it isn't hampered by the known
>> issues of a whole horizon mirror. On balance what I want is the
>> Pelorus with the polarisers as
>> well. I expect that verticality of the instrument will not be an
>> issue when using the astigmatiser but that
>> you'll just have to rock like you always do when doing sun/moon.
>>
>> Love to hear your views, and particularly if anyone
>> has used the Polaris or the Horizon Ultra.
>>
>> Regards
>>
>> Pelorus
>>
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