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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Index error by a star-star distance
From: Bill B
Date: 2008 Sep 22, 16:18 -0400
From: Bill B
Date: 2008 Sep 22, 16:18 -0400
Andres wrote: > 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, ... ? I have an Excel spreadsheet to calculate star-to-star distances. It includes corrections for the observer's altitude above sea level, barometric pressure and temperature. Inputs are SHA (or GHA of planet), declination, and Hc of the bodies at a given time; plus altitude of observer, temperature and barometric pressure. I would be happy to send you a copy if you are interested. As to averaging, the SHA's of stars are a constant for all practical purposes over a 5 to 10 minute observation period, and the angular distance is not particularly sensitive to Hc changes. If you pick a time and make observations plus/minus 5 minutes from that time any change in the angular distance would usually be far less than the ability of a man/sextant to measure it. If you program will run on a Mac OS, I would love to see it. Bill B --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---