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Subject: Re: Bubble horizon
From: Dr. Geoffrey Kolbe (geof@XXX.XXX)
Date: Tue Dec 17 2002 - 03:52:59 EST
Robert Eno wrote:
>To make a long story short, unless you can adjust the size of the bubble,
>you will experience errors; sometimes gross errors.
I, and I am sure some others on the list, would be grateful to Robert if he
could make this short story a little longer. Why is the size of the bubble
critical? Is Robert concerned that the damping of the bubble movement is a
function of bubble size, or that the accuracy with which the celestial
object can be centered in the bubble is a function of bubble size, or some
other consideration?
To answer George Huxtable's question on the sort of accuracy one should
expect from a bubble sextant. I have a Link A-12 aircraft sextant (still
available from Celestaire, last time I looked,) and I would expect an
altitude measurement to be within +/- one minute. I am disappointed if I am
two minutes out and I cannot remember the last time I was more than two
minutes out.
Geoffrey Kolbe.
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