NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Direct methods
From: John Cole
Date: 2007 Nov 01, 19:00 -0500
Re: [NavList 3723] Direct methods
Works for me too. I checked it using data from Andres Ruiz (NavList 3635). Also checked Andres’ data by independent calculation using St. Hilaire method and (printed) almanac.
Useful spreadsheet. Thanks.
John Cole
From: d walden <waldendand@yahoo.com>
Reply-To: <NavList@fer3.com>
Date: Wed, 31 Oct 2007 14:51:33 -0700 (PDT)
To: navlist <navlist@fer3.com>
Subject: [NavList 3723] Direct methods
It is of course possible, as has been pointed out, to calculate the latitude and longitude of the points of intersection of two circles of position directly with neither an estimated nor an assumed position. Nor in fact are altitudes and intercepts or any plotting needed. The intersection of cones method, described by Frank in the discussion of latitude by lunars, and shown in a previously posted FORTRAN and Maxima example can be used. A few minor changes to the programs posted are needed.
The problem is, in fact, slightly easier. It can be done with intersecting planes. The attached little spread sheet is an example of how. One enters with the altitude, declination, and GHA of two bodies. Out come the latitudes and longitudes of the two intersection points. If you have three bodies, pick a different pair, and two of the points should wind up quite close. There you are.
Seems to be working for me, but no guarantees.
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From: John Cole
Date: 2007 Nov 01, 19:00 -0500
Useful spreadsheet. Thanks.
John Cole
From: d walden <waldendand@yahoo.com>
Reply-To: <NavList@fer3.com>
Date: Wed, 31 Oct 2007 14:51:33 -0700 (PDT)
To: navlist <navlist@fer3.com>
Subject: [NavList 3723] Direct methods
It is of course possible, as has been pointed out, to calculate the latitude and longitude of the points of intersection of two circles of position directly with neither an estimated nor an assumed position. Nor in fact are altitudes and intercepts or any plotting needed. The intersection of cones method, described by Frank in the discussion of latitude by lunars, and shown in a previously posted FORTRAN and Maxima example can be used. A few minor changes to the programs posted are needed.
The problem is, in fact, slightly easier. It can be done with intersecting planes. The attached little spread sheet is an example of how. One enters with the altitude, declination, and GHA of two bodies. Out come the latitudes and longitudes of the two intersection points. If you have three bodies, pick a different pair, and two of the points should wind up quite close. There you are.
Seems to be working for me, but no guarantees.
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
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To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
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