NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: "Improved" sextants
From: hellos
Date: 2006 Jul 4, 18:47 -0500
Alex-
> "duralumin" (an alloy of aluminium) is superior to brass
> as a material for sextant frames. The booklet is of 1930's.
> Apparently C. Plath did not share this point of view.
Bear in mind that until the 70's or 80's, boatbuilders avoided aluminum because
of notorious galvanic problems. It is possible that duraluminum wouldn't handle
long-term immersion in salt spray, or that they simply didn't want to pursue
anything "aluminum" at that early time. I have no idea how the price of aluminum
alloys compared in the 30's but suspect it was still so high that only aircraft
builders could justify it. (I'd research this but I'm on the road with slow
dial-up this week.)
The image-stabilizing binocs are rather expensive, but cameras in the $300 range
manage to include image stabilization by using some much less expensive ways of
jiggling the mirror, rather than moving relatively massive lenses, and I suspect
the manufacturing cost is in the $5-10 range.
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To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
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From: hellos
Date: 2006 Jul 4, 18:47 -0500
Alex-
> "duralumin" (an alloy of aluminium) is superior to brass
> as a material for sextant frames. The booklet is of 1930's.
> Apparently C. Plath did not share this point of view.
Bear in mind that until the 70's or 80's, boatbuilders avoided aluminum because
of notorious galvanic problems. It is possible that duraluminum wouldn't handle
long-term immersion in salt spray, or that they simply didn't want to pursue
anything "aluminum" at that early time. I have no idea how the price of aluminum
alloys compared in the 30's but suspect it was still so high that only aircraft
builders could justify it. (I'd research this but I'm on the road with slow
dial-up this week.)
The image-stabilizing binocs are rather expensive, but cameras in the $300 range
manage to include image stabilization by using some much less expensive ways of
jiggling the mirror, rather than moving relatively massive lenses, and I suspect
the manufacturing cost is in the $5-10 range.
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
