NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Star sparkle in sextant image
From: Jim Thompson
Date: 2004 Sep 27, 16:24 -0300
From: Jim Thompson
Date: 2004 Sep 27, 16:24 -0300
Jared,
your post is very interesting. The simulators on that website are useful
too. After playing with them I conclud that my vision quality is not
bad, just not perfect. Obviously many suffer signficant impairment.
I have worn weak prescription glasses for
near-sightedness since age 12, and weak reading glasses since the early
40's (still only 1.25). I did not start using a sextant seriously until a
couple of years ago, after I had had laser surgery for minor retinal
degenerative changes. I am left with what I think is no
change vision in my right eye (subjectively), and a faint halo effect in my
left eye, which had the floaters that lead to the diagnosis. I use my
right eye for sextant sights. Since I have no way to compare with my vision
in my younger years, then presumably my ability to detect fine features through
the sextant is somewhat impaired, compared to young navigators. However
I got a 0.6 mile intercept on Saturday from the boat at anchor, so I
am far from blind. I could get us across the open Atlantic, but I would
certainly want GPS for landfall and the channels!.
It
would be fun to have a simulator like that for sextant observers, so that we
could construct what we see for comparisons' sake. I wonder if the Navy
has public data, or even standards, on navigator
sextant vision?
Jim Thompson
-----Original Message-----
From:
Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM]On Behalf
Of Jared Sherman
You might want to play with the interactive vision simulator at http://www.surgicaleyes.com ....
