NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Andr?s Ruiz
Date: 2010 Nov 25, 12:28 +0100
See: NP 100 Extracts from THE MARINER’S HANDBOOK
Edition 1.1 – December 2009
I have attached p87&88
Horizontal sextant angles
11.8
Where great accuracy
in position is required, such
as the fixing of a
rock or shoal, or adding detail to a
chart, horizontal
sextant angles should be used when
practicable. The
accuracy of this method, which
requires trained and
experienced observers, will
depend on the
availability of three or more suitably
placed objects.
Whenever possible about five objects
should be used, so
that the accuracy of both the fix
and the chart can be
proved.
A horizontal sextant
angle can also be used as a
danger angle when
passing off–lying dangers, if
suitably placed marks
are available. This method
should not be used
where the chart is based on old or
imperfect surveys as
distant objects may be found to
be incorrectly placed.
