NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Morris
Date: 2011 Sep 2, 16:10 -0700
Anabasis (Jeremy) has commented about this sextant. Recently I have had my hands on one to overhaul it and it seemed to me to be a well-constructed instrument, built along the lines laid down by C Plath. However, when I came to re-align it, I found that the collimating rising piece had been wrongly constructed, so that it could not possibly correct collimation error. I then checked and found two others with the same fault. Those interested can read more details on my blog post at http://sextantbook.com/2011/09/02/tamaya-collimation-blunder/
It is a simple matter to correct the construction, involving drilling and tapping two holes and inserting two grub screws.
The field of view of the 3 x 40 Galilean telescope is about 5 degrees, what one would expect from a telescope of this type. Jeremy's account of a sextant with a very large side error underlines that one should check the alignment of any instrument that one hopes to rely on.
Bill Morris
Pukenui
New Zealand
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