NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: "Improved" sextants
From: Alexandre Eremenko
Date: 2006 Jul 5, 02:23 -0500
Dear Red,
1. When I come home I will send a precise citation
from the Heath booklet on duraluminium.
The main evident advantage is the light weight.
Heath also speaks of mechanical advantages, and gives some
numbers (related to rigidity) which I do not remember.
About comparative price, I am not sure, but probably
the price of making a sextant frame is far higher than the
price of material. It could be that duralumin frame
is easier to make than a brass frame.
Notice that ALL modern manufacturs except Cassens-Plath
use an aluminium alloy. (But Cassens-Plath claims that their
sextants are "best of all", and certainly most expensive:-)
> The image-stabilizing binocs are rather expensive,
> but cameras in the $300 rang
Yes, but so far we did not apply price limitations to our
imaginary designs:-)
Two complements to my previous proposals:
1. A dipmeter will automatically solve all problems
with horizon (if the horizon is visible at all).
The height of eye will
become irrelevant, for example.
A've never seen a dipmeter "alive", neither on e-bay nor in the museums.
Only in the pictures. Russian manuals strongly recommend to
ALWAYS use it, and judging from these manuals the device was common
in the Soviet merchant marine in the 60-s.
What happened to all these devices, and why they never pop up on
e-bay, I don't know.
2. Stabilization will probably permit to attach a VERY precise
bubble horizon. As I understand, the main obstacle to the use
of very precise bubble horizon is shaking of the hand held
sextant. This would solve ALL horizon problems radically.
3. BTW, stabilized binoculars probably permit you do
observe Jupiter satellites eclipses, and return to the oldest
precise method of determining longitude:-)
I never tried.
But my general impression from testing 40x stabilized binoculars
was great. I could see antenna towers on the German shore...
from Helgoland (!!) The shore itself was well under the horizon
though I was standing rather high, on the very top of the Hellgoland
rock.
Alex.
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
From: Alexandre Eremenko
Date: 2006 Jul 5, 02:23 -0500
Dear Red,
1. When I come home I will send a precise citation
from the Heath booklet on duraluminium.
The main evident advantage is the light weight.
Heath also speaks of mechanical advantages, and gives some
numbers (related to rigidity) which I do not remember.
About comparative price, I am not sure, but probably
the price of making a sextant frame is far higher than the
price of material. It could be that duralumin frame
is easier to make than a brass frame.
Notice that ALL modern manufacturs except Cassens-Plath
use an aluminium alloy. (But Cassens-Plath claims that their
sextants are "best of all", and certainly most expensive:-)
> The image-stabilizing binocs are rather expensive,
> but cameras in the $300 rang
Yes, but so far we did not apply price limitations to our
imaginary designs:-)
Two complements to my previous proposals:
1. A dipmeter will automatically solve all problems
with horizon (if the horizon is visible at all).
The height of eye will
become irrelevant, for example.
A've never seen a dipmeter "alive", neither on e-bay nor in the museums.
Only in the pictures. Russian manuals strongly recommend to
ALWAYS use it, and judging from these manuals the device was common
in the Soviet merchant marine in the 60-s.
What happened to all these devices, and why they never pop up on
e-bay, I don't know.
2. Stabilization will probably permit to attach a VERY precise
bubble horizon. As I understand, the main obstacle to the use
of very precise bubble horizon is shaking of the hand held
sextant. This would solve ALL horizon problems radically.
3. BTW, stabilized binoculars probably permit you do
observe Jupiter satellites eclipses, and return to the oldest
precise method of determining longitude:-)
I never tried.
But my general impression from testing 40x stabilized binoculars
was great. I could see antenna towers on the German shore...
from Helgoland (!!) The shore itself was well under the horizon
though I was standing rather high, on the very top of the Hellgoland
rock.
Alex.
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
