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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Pocket sextant
From: Jim Hickey
Date: 2005 Dec 12, 09:58 -0500
From: Jim Hickey
Date: 2005 Dec 12, 09:58 -0500
A number of years ago I purchased out of curiosity a small craft sextant by Francis Barker & Son. When received the instrument appeared in excellent condition and well made.
I was interested in seeing just how well it performed in comparison to my good full sized brass sextant.
The small sextant as one would expect was difficult to use with the tiny mirrors but results could be consistently obtained within +/- about 1' under ideal conditions. In an absolute sense, the instrument performed as advertised.
What I did discover was that this sextant has an error in it through the entire arc of about 3' per 10 degrees on the arc. No perceivably perpindicularity error. No optics to contend with. I simply made a small table that I keep with the instrument.
Has anyone on this forum used one of these sextants? Has anyone had a similar experience? Maybe my expectations were too high but I was surprised by the systematic error I discovered.
Cheers,
Jim