NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Arificial Horizons and Tea
From: Doug Royer
Date: 2003 Jul 10, 10:46 -0700
From: Doug Royer
Date: 2003 Jul 10, 10:46 -0700
I got
tired of careing for and useing liquid horizons.I bought a piece of black glass
6x6 in square for $8.50.Had it polished on one side for $13.00 and it looks like
a piece of obsidian.It is very reflective.Got 2 small liquid levels for $2.50
each.A piece of 6061 aluminum 7x7 in. square, 0.064 in. thick.Drilled and tapped
for 6-32 machine bolts in each corner for leveling.Used RTV 3145 adhesive
to bond the glass(polished side up) and levels to the aluminum plate.The levels
are used in conjuction with the 4 corner bolts to level the surface of the
glass.I have been useing it for 6 weeks now and can tell you that I have no
problem seeing star images to take alt. measurements.Images of the Sun and Moon
are astonishingly clear and the point of light of a star is crisp.There is
no ripple on the glass surface to distort the relected images and the bothersome
problems of wind and fluid have been eliminated.It is light in wieght yet robust
and small in size.Throw it and a plastic sextant into the backpack and off you
go not careing about carrying fluids other than to drink.Something to think
about in a desert environment.
All
that said,I live in a very arid part of the south west that has very little
humidity and atmospheric haze and at night very little man made light
that washes out or interfers with the light of stars.The wind can howl out
here and was the biggest problem in useing a fluid horizon.This cost me about as
much as a new Davis plastic horizon.
-----Original Message-----
From: Wolfgang Bosswick [mailto:wolfgang.bosswick@SOWI.UNI-BAMBERG.DE]
Sent: Thursday, July 10, 2003 00:10
To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
Subject: Re: Arificial Horizons and TeaI guess, tea works fine for several good reasons: It is usually available without problems, you can drink it after the shots (while unboiled pure water might be risky), and finally, tea contains aromatic oils - they often leave brown traces on a white cup. These oils likely form a one mol thin film on the water, calming its surface. With pure water, the lightest air breeze causes a scattered sight, and you have to wait for seconds until the waves disappear.
