NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Alexandre Eremenko
Date: 2012 Mar 11, 07:41 -0700
Thanks to all who answered on "Complete on board Cel Nav".
Indeed a 2011 edition can be found in electronic for about $10.
Then one can print and bind it.
I wanted to bring to everyone's attention the very good conditions
for planet observation which exist now, in March 2012. Yesterday I could see
all 5 planets in one night.
Mercury was hardest of course, but 30 min after the sunset I was able to find it
using my binocular, and 15 minutes later it was possible to see it with
the naked eye, if one knows exactly where it is. Binocular helps a lot in finding it.
Once it is found it can be seen with a naked eye. It sets (behind the trees which obscure my horizon) about 1 hour after the Sun.
Venus one can see with a naked eye even before the sunset. A sextant helps
a lot in this task. I use the following method. Compute the Sun-Venus distance
approximately with the usual formula for solving a triangle (no corrections
are needed for a rough approximation). Set the sextant on this distance, point
it to the Sun, so that it is visible through a horizon mirror, and slowly rotate
it around the telescope axis until Venus is caught in the index mirror.
(Of course, one needs a horizon filter and no index filter:-)
Once Venus is found, you can see it with a naked eye.
Alex.
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