
NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Jeremy C
Date: 2013 Apr 16, 08:39 -0700
Frank,
I think that my examples from January would be good to use. Real shots from sea that give reasonable exercises for the moon and several 1st order stars , and couple planets (fairly accurate even) in the Eastern Hemisphere. They can all be solved via HO 229 and the NA.
Double second differences are a feature of HO229, especially when using the front/back cover interpolation tables. As mentioned, these are demarked by the "d" in italics and with a "*" These are found in the USCG test pool, but usually rear their ugly heads in the "Management" level test (Chief Mate unlimited). While it might be nice to see in a "basic" class, it might be moot, but if the instructor wants it, we can give him one. The trouble is finding one. The best example might be constructed backwards from the table, with a selected entry into HO229 that has the marking, and then making the sight up that fits the entering arguements. I have experienced them mostly with stars.
I would keep watch error in there, but not chronometer error. Temp/Pressure for low altitude sights to show the example of how to use the correction graph in the NA. I know that at least one of my recent star sights and the moon sight should have T/P corrections added.
I would like to do my examples in the traditional way, but I don't have a nautical almanac with me so I can't do it "properly" with all of the tables that I would use at sea.
Frank, do you have a copy of the 2013 NA that I could use this weekend? It wouldn't take me too long to fire off these sights with HO229. There are only about 15 of them.
Sadly I have no sunlines to offer as I don't shoot them too often.
Jeremy
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