NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Line of Position Fix
From: Bruce J. Pennino
Date: 2012 Oct 18, 20:34 -0400
From: Bruce J. Pennino
Date: 2012 Oct 18, 20:34 -0400
Hello:
I'm a little ahead of you on the learning curve,
but I understand your situation. I first tried to find sites where I could get
at least two day light sights 30 D ZN apart, with a good or
reasonably good day time horizon. Even if I had to use the dip short
table. It took a while for me to really understand "swinging the sextant".
It is really a rotating and swinging motion. Not hard , just takes
practice. I've found that sight even with altitudes as low as 15 D can give good
results. I almost always take three or five sights and determine the increment
between them. Sometimes I plot them. Usually one or two sights are clearly
better than others. If I get two good consecutive sights a minute or so
apart I average them.
Day time moon shots are excellent for
practice, using upper or lower limb and sometimes you can get sun sights and
moon sights at the same time. I struggle with twilight sights to the point I've
made a mirror artificial horizon which I'm getting better at. Go to the
U.S. Naval Observatory web site and look at data services. I really love
this site because you submit your location and time and it will give you the
visible celestial bodies, their ZN and altitudes. Then you know which ones
are available, and where to look. Rotating star charts are also
very helpful. They cost $10 or so. Some star are
very easy to spot after a while, but the horizon at night is my real
problem. Everyone says the morning horizon is easier. I'm going to try that in a
week or so before the clocks change. At night certain stars are visible
early, northern cross and others mentioned.
Good luck
Bruce
----- Original Message -----From: Debra HillmanTo: NavList@fer3.comSent: Thursday, October 18, 2012 3:21 PMSubject: [NavList] Line of Position FixCould somebody help me with my problem . I am learning on my own at present from books on celestial navigation.I need to get a fix with two lines of position but not sure which celestial body other than the sun and the best times of the day to achieve the fix.
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