NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Andrés Ruiz
Date: 2008 Sep 22, 16:23 +0200
I am writing an article about “Index error by a
star-star distance”.
Unfortunately there is not much information about this
subject, or I can’t found it. Anybody has any source of information; old
books, papers, … ?
The algorithm is a simplification of the Lunar Distance
method, taking into account that there is no semidiameter or parallax.
The calculated star-star distance is compared with the
observed one to obtain the sextant error, that is the index error plus the
instrumental error inherent to the sextant.
For those who want to shoot stars and obtain his IE, the
program is available via e-mail under request.
Feedback is welcoming. My two sextants have a have a
negligible error; I can’t check the results for a real significant IE.
I think the hardest part is to take the distance, is no easy
to do this with two stars, and special skills and background is needed.
A series of up to ten observations are needed in order to
obtain the mean UT and Hs.
References:
The Sextant and Its Applications. William Simms, (free at
google books)
Andrés Ruiz
http://www.geocities.com/andresruizgonzalez
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