NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Advice concerning sextants
From: James N Wilson
Date: 2010 Feb 22, 15:45 -0800
From: James N Wilson
Date: 2010 Feb 22, 15:45 -0800
Patrick:
I've over the years put together some points to consider in buying a
sextant. I'll offer it here again, just in case it might help.
Jim Wilson
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THE SEXTANT -- as seen by the small boat sailor
Size -- small ones stow easily -- accuracy O.K.
Telescope -- less than 4 power; 2x to 3x recommended: 6-7X -- NO! --
12X??
- remove in rough seas
- big objective lens for lots of light
Horizon Glass -- half clear, half silvered; not cut off at edge of
mirror
- large -- big round ones better (disadvantage of small sextant)
- half silvered -- sometimes difficult to see horizon
Vernier on micrometer drum -- not required
- accuracy doesn't warrant
- can lead to reading errors
Shades -- all O.K. -- polarized may be easier or quicker
Feel -- weight, ease of movement, etc. -- try it!
- weight -- some heavy, [steadier] -- some light, [less fatigue]
- personal preferences govern
Built-in Light -- very handy, can be used to illuminate forms and
watch
Bubble Sextant -- no good for sights from boat
- O.K. with natural horizon
Astigmatizer -- I don't use
- hard to hold body in field
Plastic -- O.K., good spare -- accuracy questionable, but probably
O.K.
Fine points
- shade interference with field
- drum not pinned to shaft
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